What is Inventory Management? How It Works, and Methods

What is Inventory Management? How It Works, and Methods

Inventory management goes far beyond simply storing spare parts. It’s the lifeline of industrial maintenance, ensuring your operation runs smoothly and without costly interruptions.

Efficient inventory systems keep critical parts and tools within reach for preventive repairs, eliminating delays caused by emergency purchases or downtime. 

This level of preparedness can help you minimize unexpected expenses and increase operational efficiency.

The bottom line is simple: well-organized inventory and effective asset tracking make maintenance more reliable and controlled.

Picture this: knowing exactly where to find every tool, part, or component at the moment you need it.

In this article, we’ll take a closer look at how an optimized industrial inventory doesn’t just keep machines up and running but also reduces waste and drives cost savings throughout your entire operation.

What Is Inventory Management?

Inventory management is the process of overseeing and controlling a company’s inventory, which includes raw materials, components, and finished products. 

It ensures that the right quantity of stock is available at the right time to meet customer demands while minimizing storage costs and avoiding excess inventory. 

Effective inventory management is a critical aspect of supply chain optimization and plays a key role in improving operational efficiency and profitability.

Essential Types of Inventory for Industrial Maintenance

There are multiple types of inventory, each serving a distinct and essential purpose within maintenance inventory management.

Let's explore the three main types:

  • General inventory of maintenance parts and materials
  • Rotating inventory of critical items
  • Inventory of maintenance tools and equipment

1. General Inventory of Maintenance Parts and Materials

The general inventory includes all components and materials needed to assign tasks and perform routine maintenance.

Think of it as the main hub for everything essential to keeping daily operations running smoothly. From bolts and nuts to electric motors and sensors, it houses a wide range of items.

But why keep such a varied stock? Simple: to prevent production from grinding to a halt due to a missing part.

Imagine having to shut down an entire production line because you ran out of a basic fuse. This type of inventory exists to ensure that never happens.

2. Rotating Inventory of Critical Items

Here we enter territory that requires more attention: the rotating inventory of critical items. 

These are components that, if unavailable, could cause prolonged interruptions to a production line—and their replacements can come with a hefty price tag.

Items like bearings, electronic circuits, or even custom parts designed for specific machines fall into this category.

Maintaining this type of inventory requires a proactive approach, regularly reviewing and restocking based on how frequently the items are used and how critical they are to maintenance operations.

3. Inventory of Maintenance Tools and Equipment

Keeping an inventory of essential equipment for carrying out maintenance is crucial. 

This includes items that support machine repairs and maintenance work, such as precision screwdrivers, multimeters, welders, and lifting platforms.

When working with these tools, organization and upkeep are key. Keeping everything in good condition not only speeds up repair times but also ensures safety procedures are met.

Lost time searching for tools that should be readily available is one of the biggest obstacles to productivity and equipment uptime.

Step-by-Step Guide to Effective Inventory Management

Proper inventory management has a direct impact on your operation's efficiency. In industrial maintenance, it requires accuracy and careful planning to drive improvements in performance and key metrics like OEE.

We’ll walk through the process step by step to make sure everything is covered.

Step-by-Step Guide to Effective Inventory Management

1. Identifying and Organizing Parts and Materials

The first step is establishing a clear and unique system to identify each part and material in your inventory.

While it might seem challenging, tools like barcodes or numerical codes can streamline tracking and management, making the process more efficient.

For instance, you could label a motor as "Motor AC-1234," where "AC" denotes the motor type, and "1234" is a unique identifier.

This kind of coding system makes it easier to locate items in inventory and reduces the risk of errors when restocking.

2. Counting and Recording Inventory

Physical counts are the backbone of inventory management. This step involves verifying each item in stock and accurately documenting its quantity.

While it sounds simple, it can be time-consuming and labor-intensive.

That’s where tools like barcode scanners come in handy—they automate data entry, save time, and reduce the risk of mistakes.

Imagine the difference between manually counting hundreds of bolts and simply scanning a code that automatically records the quantity and specifications?

The second option saves time and significantly lowers the chance of errors.

3. Syncing Data with Your Maintenance Management System

Once the physical count is complete, it’s crucial to reconcile the collected data with the records in your CMMS (which stands for Computerized Maintenance Management System) or EAM (Enterprise Asset Management) software.

This step is essential to spot and address any discrepancies between what’s on record and what’s actually in stock. Also, by syncing real-time data with CMMS maintenance software, teams can better predict inventory needs and streamline operations.

For instance, if the CMMS solution indicates 50 units of a specific bearing but the physical count shows only 45, it could signal a recording error or an untracked usage that needs further investigation.

4. Divergence Analysis and Necessary Adjustments

Divergence analysis is the process of investigating inconsistencies between recorded inventory data and actual stock levels.

This step often uncovers issues like theft, loss, or simple data entry mistakes. Once discrepancies are identified, they must be corrected in the system to ensure accurate stock records.

Adjustments might be as straightforward as updating a quantity, but they can also require reviewing and improving material handling or storage practices.

By the end of this process, you'll not only have an accurate inventory but also valuable insights to optimize maintenance inventory management.

But what can you do with this information? Reduce unnecessary costs and increase operational efficiency.

When you know exactly what’s in stock, what’s needed, and what’s being used, you eliminate redundant purchases and reduce excess or outdated inventory. This means less capital tied up in unnecessary stock and more resources available to invest in critical areas of your operation.

Additionally, by keeping essential maintenance items on hand, you reduce downtime, improve productivity, and ensure your plant operates with greater responsiveness.

Ultimately, each step in this process doesn’t just refine your inventory management—it reinforces the efficiency and reliability of your entire operation.

Increase Plant Efficiency and Minimize Costs

Asset Management vs. Inventory Management

Asset inventory management (AIM) is the systematic process of tracking and maintaining a company’s internal resources—such as machinery, vehicles, and software—that support daily operations.

Asset management and inventory management are distinct processes, each serving a unique purpose within an organization. 

Asset management focuses on tracking, maintaining, and optimizing a company’s internal resources, such as machinery and equipment, throughout their lifecycle. It ensures assets are regularly inspected, repaired, and utilized efficiently.

On the other hand, inventory management deals with managing items intended for sale or production, such as raw materials and finished goods. 

While asset management monitors tools for running the business, inventory management tracks goods that flow through the business.

asset management vs inventory management

Maintenance Stock Management: Best Practices

Before diving headfirst into your inventory, it’s worth taking a moment to reflect. Maintenance stock management is in a league of its own, requiring meticulous attention due to its direct impact on operational efficiency.

So, what sets “maintenance stock” apart from your regular inventory of products, supplies, or raw materials?

The key difference lies in the critical nature of its availability and reliability. Simply put, maintenance stock exists to ensure smooth operations, minimizing the risk of unplanned production downtime.

Now, let’s get straight to it. Here are some best practices to help you streamline and optimize your maintenance inventory management approach.

ABC Classification of Stock Items

The ABC curve is an inventory management technique that categorizes items into three groups—A, B, and C—based on their value and usage frequency.

  • ‘A’ Items: High-value items that are used less frequently.
  • ‘B’ Items: Moderate-value items with a medium frequency of use.
  • ‘C’ Items: Low-value items that are needed more often."

For instance, a critical but expensive component that’s rarely replaced would fall into category ‘A.’

To make this concept clearer, take a look at the chart below:

ABC Classification of Stock Items - ABC Curve

This approach allows you to prioritize resources effectively, ensuring efficiency in inventory management.

Establishing Minimum Quantities and Reorder Levels

Defining minimum inventory levels and reorder thresholds is essential to prevent shortages or overstocking.

Minimum Stock: The baseline quantity you should never go below to avoid production stoppages.

Reorder Level: The inventory threshold that signals when it’s time to restock an item, based on historical consumption patterns.

To get it right, ask yourself: “What are the risks of operating below this level?” Then, make the necessary adjustments to ensure smooth operations and maintain efficiency.

Consumption and Inventory Turnover Analysis

Understanding consumption trends is key to managing inventory effectively. Analyzing usage patterns allows you to proactively adjust stock levels and fine-tune your purchasing strategy.

Inventory turnover—how often items are used and restocked within a given timeframe—is a critical metric for efficiency.

High-turnover items may require additional safety stock to avoid shortages, while low-turnover items could signal overstocking or even obsolescence. Keeping an eye on these patterns helps you strike the right balance and optimize inventory performance.

Physical Organization of the Maintenance Warehouse

If you think a good maintenance warehouse only needs great software to run efficiently, think again. Physical organization plays a crucial role.

Why? Because a well-organized warehouse saves time and minimizes errors.

Every item should have a designated spot that’s clearly labeled and easy to access. Implementing clear signage and leveraging technologies like QR codes for fast tracking are highly recommended practices.

Now, ask yourself: how much time does your team spend searching for items?

By adopting these strategies, you can transform inventory management from a daily challenge into a competitive edge.

When you focus on efficiency, accuracy, and responsiveness, you also address an often-overlooked factor: employee satisfaction.

A well-organized warehouse fosters a safer, more harmonious, and streamlined work environment—all of which have a direct impact on your team’s productivity.

So, how does your warehouse stack up today? Is it optimized to fully support your predictive maintenance goals?

Inventory Management Methods

Inventory management methods are essential strategies that businesses use to optimize the flow of goods and materials.

Effective inventory management helps companies balance supply and demand, minimize costs, and improve customer satisfaction. 

By choosing the right method, organizations can reduce waste, streamline operations, and ensure they always have the right products available at the right time.

Each method caters to specific business needs and operational environments, whether it’s minimizing inventory levels, ensuring timely production, or calculating the most cost-effective order quantities. 

Below, we’ll explore four of the most widely used inventory management methods: 

1. Just-in-Time Management (JIT)

Just-in-Time (JIT) is an inventory management method focused on reducing waste by receiving goods only as they are needed for production or sales.

This approach minimizes inventory holding costs and enhances efficiency. Originally from Japan, JIT is famously associated with Toyota's production system.

Key Benefits:

  • Reduces inventory holding costs.
  • Minimizes waste by aligning production with demand.
  • Enhances production efficiency and flexibility.
  • Strengthens supplier relationships to ensure timely deliveries.

Challenges:

  • Requires highly reliable suppliers.
  • Susceptible to disruptions in the supply chain.
  • Requires precise demand forecasting and inventory tracking.

JIT is ideal for companies with stable, predictable demand and robust supply chain systems, such as automotive manufacturers or electronics producers.

2. Materials Requirement Planning (MRP)

Materials Requirement Planning (MRP) is a system that calculates the materials and components needed to manufacture a product.

By analyzing the production schedule, current inventory levels, and lead times, MRP ensures that the right materials are available at the right time.

Core Components:

  • Master Production Schedule (MPS): Outlines what needs to be produced and when.
  • Bill of Materials (BOM): A detailed list of materials and components required.
  • Inventory Records: Tracks current inventory levels to avoid overstock or shortages.

Key Benefits:

  • Optimizes inventory levels to reduce excess stock.
  • Improves production planning and scheduling.
  • Reduces the risk of material shortages.

Challenges:

  • Relies heavily on accurate data input.
  • Requires sophisticated software and trained personnel.
  • Less effective in environments with highly variable demand.

MRP works best for manufacturing companies with complex production processes and a need to manage multiple components and materials.

3. Economic Order Quantity (EOQ)

Economic Order Quantity (EOQ) is a formula-based inventory management approach that calculates the ideal order quantity to minimize total inventory costs. 

These costs include ordering costs (e.g., shipping) and holding costs (e.g., storage).

Formula:

Economic Order Quantity (EOQ) Formula

Where:

  • D: Annual demand.
  • S: Ordering cost per order.
  • H: Holding cost per unit per year.

Key Benefits:

  • Reduces total inventory costs.
  • Balances ordering frequency with storage costs.
  • Helps in budget planning for inventory management.

Challenges:

  • Assumes constant demand and lead time, which may not be realistic.
  • May not accommodate bulk discounts or variable costs.

EOQ is best suited for businesses with stable demand and predictable ordering costs, such as retailers or distributors.

4. Days Sales of Inventory (DSI)

Days Sales of Inventory (DSI) is a financial metric that indicates the average number of days a company takes to sell its inventory during a specific period.

It is a key performance indicator for inventory efficiency.

Formula:

Days Sales of Inventory (DSI) Formula

Key Benefits:

  • Helps assess inventory liquidity.
  • Identifies inefficiencies in inventory management.
  • Provides insights into cash flow and operational performance.

Challenges:

  • A high DSI indicates slow inventory turnover, potentially leading to higher holding costs.
  • A very low DSI may indicate insufficient inventory to meet demand.

DSI is a universal metric used across industries but is particularly useful for companies looking to benchmark performance and improve inventory turnover.

5. LIFO and FIFO

LIFO (Last In, First Out) and FIFO (First In, First Out) are inventory valuation methods that determine the order in which goods are sold or used and how inventory costs are allocated to the cost of goods sold (COGS) and remaining inventory.

LIFO

LIFO, or Last In, First Out, is an inventory valuation method where the most recently acquired or produced goods are sold or used first. This method assumes that the latest inventory items are moved out first, leaving older stock as inventory.

Key Benefits:

  • Tax advantages: In times of rising costs, LIFO can reduce taxable income by matching higher inventory costs to current revenues.
  • Cost alignment: It aligns the cost of goods sold (COGS) more closely with current market prices, providing a realistic profit margin during inflationary periods.

Challenges:

  • Inventory aging: Older inventory might remain unsold, leading to obsolescence or spoilage.
  • Not allowed in all countries: LIFO is prohibited under International Financial Reporting Standards (IFRS), though it is accepted in the U.S. under GAAP.
  • Complexity: Requires meticulous record-keeping to track inventory layers.

LIFO is suitable for industries where inventory costs fluctuate frequently, such as commodities, oil, and manufacturing.

First In, First Out (FIFO)

FIFO, or First In, First Out, is an inventory valuation method where the oldest inventory items are sold or used first. This method assumes that goods are sold in the order they are acquired or produced, leaving the most recent items as inventory.

Key Benefits:

  • Ease of use: FIFO aligns with the natural flow of goods, especially in industries with perishable items like food or pharmaceuticals.
  • Accurate balance sheets: During periods of rising costs, FIFO ensures that older, lower-cost inventory is used first, which can increase the value of remaining inventory on the balance sheet.
  • Global acceptance: FIFO is allowed under both IFRS and GAAP, making it a versatile method for global companies.

Challenges:

  • Higher taxes during inflation: By matching older, lower-cost inventory to revenues, FIFO may lead to higher taxable income during inflationary periods.
  • Profit distortions: It may overstate profitability if inventory costs rise significantly over time.

FIFO is ideal for businesses with time-sensitive or perishable inventory, such as grocery stores, retail, or pharmaceuticals.

Key Differences Between LIFO and FIFO

Key Differences Between LIFO and FIFO

Benefits of Efficient Inventory Management

It’s no secret that effective inventory management can transform the way a company operates.

But have you considered the concrete benefits that a well-organized and strategic approach to inventory can bring to your operation?

Let’s dive into three key advantages that make all the difference.

Increased Equipment Uptime

Effective inventory management directly impacts asset health, ensuring that equipment operates at peak performance by minimizing the risk of unplanned downtime.

When the right parts and materials are readily available for repairs and maintenance, downtime is significantly reduced.

Just think about it: if a critical component fails and the replacement is already in stock, the repair can be done immediately, instead of waiting days or weeks for a spare part.

This doesn’t just keep production running smoothly; it also boosts asset performance and gives your business a competitive edge.

Now imagine the impact on productivity if every machine downtime could be cut by hours or even days. That’s the power of having a well-managed inventory.

Cost Savings on Inventory and Emergency Purchases

Efficient inventory management doesn’t just keep operations running—it also significantly reduces maintenance costs.

By implementing a well-organized system, you can maintain just the right stock levels, balancing demand with the predictability of usage.

In practice, this eliminates the need to overstock items that may become obsolete or expire before they’re even used.

Additionally, avoiding last-minute purchases—often accompanied by inflated costs or unfavorable payment terms—allows your company to negotiate better deals with suppliers.

This is called strategic purchasing planning, and it means more money stays in your pocket.

Greater Precision in Maintenance Planning

Efficient inventory management ultimately leads to more precise and reliable maintenance planning.

With accurate data on stock levels and the usage rates of each item, scheduling tasks and planning preventive maintenance activities become much more effective.

This allows you to organize maintenance schedules with confidence, knowing the necessary resources will be available exactly when needed.

This level of predictability doesn’t just improve efficiency—it also enables smarter allocation of resources, including labor hours and equipment, ensuring a more streamlined operation.

CMMS Implementation for Inventory Management

When inventory management runs seamlessly, the benefits ripple across your entire operation. Production stays on track, costs from overstocking or outdated items are reduced, and teams are empowered to perform their tasks more effectively.

Integrating inventory management with enterprise resource planning (ERP) systems takes these advantages even further. 

By combining real-time monitoring with predictive analytics, you gain full visibility into your inventory—knowing exactly what’s in stock, what’s running low, and what’s no longer needed.

At Tractian, our solutions are designed to simplify this process.

Aside from tracking inventory, Tractian CMMS offers features like work order management, scheduling preventive maintenance, and handling work requests, giving you complete control over your maintenance workflows. 

With robust asset lifecycle management tools, you can monitor equipment performance, plan for replacements, and extend the life of your critical assets, all while ensuring maximum uptime and efficiency.

Modern inventory management tools allow teams to track inventory levels, analyze trends, and predict future needs with unmatched precision. When integrated into ERP systems, these tools create a unified flow of information across procurement, maintenance schedules, and financial planning.

Real-time inventory data supports smarter, data-driven decisions in the supply chain, helping your operation avoid costly disruptions and maximize efficiency.

With these tools, maintenance teams can act proactively, ensuring they always have the right resources — whether it’s a critical spare part or materials for a major repair.

Take control of your inventory management, reduce costs, and keep your operations running at peak performance.

Get to know Tractian's Asset Management Software

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