When it comes to using up supplies in your shop, you should always use the newest supplies first — is actually false. Learn why the FIFO method is the right approach and how to apply it properly.
There’s a common misconception worth addressing right at the start: when it comes to using up supplies in your shop, you should always use the newest supplies first. That statement is false, and following it will cost you money. The correct principle is exactly the opposite. You use the oldest supplies first. This is called the FIFO method, short for first in, first out, and it applies to everything from refrigerants and chemicals to filters, gaskets, and lubricants sitting on your shop shelves. Understanding why this matters, and how to set it up in practice, is one of the simplest ways to run a tighter, less wasteful operation.
What Does FIFO Require?
First in, first out is an inventory management method where the oldest stock gets used before newer stock. What does FIFO require in a shop context? It requires a few basic habits:
- Organized storage where older items are always at the front. When new supplies arrive, they go behind or beneath existing stock. You pull from the front, which means you’re always reaching for what’s been there longest.
- Date labeling on supplies that don’t have clear expiry dates. Some products come with printed expiry dates. Others don’t. For those, writing the received date on the container or package when it arrives takes seconds and eliminates any guesswork later.
- Regular shelf checks. FIFO only works if someone is actually looking at what’s there, verifying that products haven’t expired, and rotating stock when new deliveries come in.
- A receiving process that builds rotation in. If the person receiving deliveries doesn’t understand the system, they’ll stack new items on top of old ones out of convenience. One clear procedure fixes this.
The goal of FIFO is to ensure that products with a limited shelf life get used before they degrade. A shop that consistently pulls from the front of the shelf spends less on waste, reduces the risk of using degraded materials on customer vehicles, and maintains better inventory accuracy.
Why the “Newest First” Approach Is a Problem
Using newer supplies first sounds harmless. In practice it creates a specific problem: older supplies sit at the back of the shelf and get forgotten. Over time, they expire, degrade, or become unusable. You end up throwing away inventory that you paid for.
Some shop supplies degrade in ways that are obvious. A sealant that’s gone hard in the tube, a can of refrigerant that’s past its service date, a bottle of brake fluid that’s absorbed moisture over time. These are easy to catch. Others degrade in ways that aren’t visible until the product fails in use. That’s a worse outcome.
The financial argument is simple. Every time an expired product gets thrown out, you’ve paid for it twice: once when you bought it, and once when you buy its replacement. Multiply that across a full year of supplies and the waste adds up. FIFO eliminates most of it.
The FIFO Method Applied Across Different Supply Types
Not all shop supplies age the same way, but the first in, first out principle applies across the board.
Chemicals and fluids: Brake fluid, coolant, transmission fluid, refrigerants, and cleaning solvents all have shelf lives. Some are sensitive to temperature fluctuations. Others absorb moisture or oxidize when containers are opened. Store them with the oldest containers in front, check dates regularly, and never use a product past its stated service date.
Gaskets, seals, and O-rings: Rubber components degrade over time even in storage. Heat, UV exposure, and ozone in the air break down the material. A gasket that looks fine on the shelf may fail faster than expected on a vehicle if it’s been sitting for two or three years. FIFO keeps the oldest rubber components moving out of inventory before they become a liability.
Filters: Oil filters, air filters, and fuel filters generally have longer shelf lives, but they’re not immune to packaging damage, moisture, or contamination from poor storage conditions. Rotate them the same way you rotate everything else.
Adhesives and sealants: These are often the worst offenders in shops that don’t rotate stock. A tube of silicone sealant or threadlocker that’s been sitting at the back of a drawer for two years may be partially cured and unusable. Date everything when it arrives.
Lubricants and greases: These can separate, oxidize, or develop contamination over time. Store them in sealed containers, follow FIFO, and dispose of anything past its recommended shelf life.
Refrigerant Handling: A Separate Set of Rules
Shops that work with refrigerants deal with a specific regulatory environment on top of standard inventory concerns. One thing worth stating directly: shops cannot mix refrigerants. Different refrigerant types have different chemical compositions, pressure ratings, and compatibility profiles. Mixing them contaminates the entire charge, can damage vehicle AC systems, and creates a product that can’t be properly recovered or recycled.
Refrigerant cylinders should be stored upright, in a cool area away from heat sources, and clearly labeled. Recovered refrigerant must be kept separate from virgin refrigerant and handled according to EPA Section 609 regulations in the United States. Proper recovery equipment is required before opening any AC system.
FIFO applies here too: if you have multiple cylinders of the same refrigerant type, use the oldest one first. Check certification dates on recovery equipment and cylinders. Refrigerant that’s been stored improperly or for too long may not meet purity standards for reuse.
Storing Parts Outside: The Environmental Risk That’s Easy to Underestimate
A common assumption in shops is that storing parts outside doesn’t cause any environmental risks as long as the items are covered. That assumption is wrong, and it can create both regulatory and practical problems.
Covering items with a tarp reduces weather exposure, but it doesn’t eliminate the risks:
- Fluid leaks from stored parts. An old engine block, a transmission, or a differential sitting outside likely contains residual fluids. Rain and weathering can cause those fluids to leach into soil and groundwater. This is an environmental violation regardless of whether the parts are covered.
- Refrigerant release from stored AC components. Compressors, condensers, and hoses that haven’t been properly evacuated can release refrigerant as they degrade. Refrigerants are regulated substances, and releasing them is a violation of federal law.
- Battery storage. Lead-acid batteries contain sulfuric acid and lead. Stored outside, a deteriorating battery can leak acid into the ground. Even under a tarp, this is an environmental hazard.
- Temperature effects on stored fluids. A covered container of fluid sitting in direct sun can reach temperatures that accelerate degradation, cause containers to expand and leak, or compromise product integrity.
The short version: covered storage outside reduces weather damage to parts. It does not address the environmental risks that come from fluid contamination, refrigerant release, or chemical leaching. Those require proper containment, storage protocols, and often secondary containment like drip pans or sealed storage bins.
Setting Up FIFO in a Real Shop Environment
Getting a FIFO system running doesn’t require a complex overhaul. Here’s a practical starting point:
- Do a full shelf audit. Pull everything out, check dates, dispose of anything expired or clearly degraded, and note what’s close to expiry so it gets used first.
- Label everything without a clear date. Write the received date on the container in marker. This takes ten seconds per item and eliminates ambiguity.
- Set a standard for incoming deliveries. New stock goes behind old stock. Every time. This becomes automatic with a bit of practice.
- Designate someone to do a monthly check. It doesn’t have to be a dedicated role, but someone needs to walk the shelves periodically and catch anything that’s being missed.
- Track what you’re throwing away. If you’re regularly discarding expired product of a specific type, that’s a signal to order less of it at a time. The FIFO system makes this pattern visible.
Good inventory management in a shop isn’t glamorous work, but it directly affects profitability and the quality of work going out the door. A shop that consistently uses fresh, properly stored materials produces better results than one that occasionally installs something that’s been sitting in a corner for three years.
For shops that also handle client-facing materials or printed documentation, the same discipline around organization matters. A well-organized shop and a clean, professional appearance go together. The fonts and visual presentation on signage, invoices, and customer-facing materials communicate the same attention to detail that good inventory management reflects. A clean geometric typeface like Montserrat signals professionalism without effort. For something with more warmth suited to customer communications, Nunito keeps things approachable and readable across formats.
Key Takeaways
- When it comes to using up supplies in your shop, you should always use the newest supplies first is false. The correct method is FIFO: first in, first out.
- What does FIFO require? Organized storage with oldest items at the front, date labeling, regular shelf checks, and a consistent receiving process.
- Different supply types age differently, but the rotation principle applies to all of them: chemicals, rubber components, filters, adhesives, lubricants, and refrigerants.
- Shops cannot mix refrigerants. Different refrigerant types must be kept separate, and recovered refrigerant must be stored and handled according to regulatory requirements.
- Storing parts outside does not eliminate environmental risks simply because items are covered. Fluid leaks, refrigerant release, and chemical contamination are risks that require proper containment, not just a tarp.
- A monthly shelf audit and a clear receiving procedure are the two most effective tools for keeping a FIFO system working in a real shop environment.
The principle is simple. Oldest stock out first. Everything else follows from that.