A missing $15 part can cost a full return trip. That is the whole case for truck stock in one sentence. The other half of the story is that every part on every truck is cash sitting in a van, so the goal is not to carry more but to carry the right things.
Truck stock in plain English
Take an example electrician on a service call for a dead circuit. She finds a failed 20-amp breaker. If the right breaker is on the truck, she swaps it, tests it and leaves with the job done. If it isn't, she either drives to the supply house mid-day (unpaid by the customer, paid by you) or books a return visit.
Truck stock is the set of parts that decides which of those happens. It varies by trade, by truck type and even by service area: a truck that works older housing stock needs different parts from one that works new construction.
How do you build a truck stock list?
- 1
Pull 6 to 12 months of parts usage
From invoices or job records: every part used on service jobs, with how many times and on how many jobs.
- 2
Add the return-trip parts
Parts that caused a return visit because they weren't on the truck, even if they're used less often.
- 3
Rank and cut
Keep parts used often enough to justify the space and cash. Cut anything that hasn't moved in a year unless it's a known return-trip saver.
- 4
Set min and max per truck
Minimum covers usage until the next restock; maximum caps the cash on board.
- 5
Standardize by truck type
One template for service trucks, another for install trucks, adjusted where a tech's work genuinely differs.
The ranking step is where most lists go wrong. Ranking only by dollars used puts expensive, rarely used parts at the top. Ranking only by count ignores that some cheap parts save expensive trips. The van that pays for itself walks through an ABC analysis and a break-even carry test on a 24-part example.
A worked carry decision
Is it worth carrying a part? Compare what it costs to carry against the return trips it saves.
| Example part | Carry it? | Reasoning |
|---|---|---|
| Dual run capacitor, common size | Yes, 3 to 4 per truck | Used weekly; a missing one costs a return trip |
| Universal igniter | Yes, 2 per truck | Common on no-heat calls in winter |
| Specific ECM blower motor | No, stock in warehouse | Expensive, many variants, used a few times a year |
| Specialty control board | No, order per job | Model-specific; carrying one per truck ties up cash |
A rough way to weigh it: an example return trip of 1.5 hours and 20 miles costs about $88.72 at June 2026 BLS compensation for repair occupations ($49.01 an hour worked)1 and the IRS business mileage rate of 76 cents a mile from July 1, 2026.2 A part that prevents even a few of those trips a year usually pays for its place on the truck.
How should you restock and count trucks?
| Restock from usage | Fixed weekly refill | |
|---|---|---|
| How it works | Parts used on invoices trigger a refill to max | Tech or warehouse tops up to a list each week |
| Accuracy | High, if invoicing is accurate | Depends on counts |
| Effort | Low once set up | High, every truck every week |
| Main risk | Parts used but not invoiced go missing | Over- or under-stocking between refills |
Whatever you choose, count. A cycle count of a few items per truck each week catches drift; a full count monthly or quarterly resets the record. Anything that keeps coming up short is either being used without being invoiced or walking off the truck.
Truck stock health check
- Every item on the truck is on the stock list, with a min and max
- Parts come off the truck record when they're invoiced
- Restock requests are filled within a day or two
- Counts are reviewed and approved before they change stock
- Items with no movement in 12 months are pulled back to the warehouse
- Return trips coded 'parts' are reviewed monthly
Truck stock and taxes
How inventory is treated for tax depends on your business's size and accounting method. IRS Publication 334 says a small business taxpayer, one with average annual gross receipts of $31 million or less for the three prior tax years and not a tax shelter, can choose not to keep an inventory for tax purposes and can instead treat it as non-incidental materials and supplies, deducted when used.3 That figure is for 2025 returns and is indexed for inflation. Ask your tax preparer which method applies before you change anything.
How truck stock works in TradesWork
Inventory in TradesWork treats every warehouse and truck as a stock location with on-hand quantities, value at cost and items below minimum. When a technician puts a tracked material on an invoice, it comes off their truck. You set a min and max per item for each truck, and replenishment refills anything below its min up to its max, from the warehouse first, then by drafting purchase orders to the preferred vendor.
Techs request restock and count their truck from the field app with the barcode scanner, even with no signal, and counts wait for office approval before they change stock.
Good truck stock is one of the biggest levers on first-time fix rate.
Footnotes
-
Employer Costs for Employee Compensation, June 2026, Table 4, U.S. Bureau of Labor Statistics. Private industry, installation, maintenance and repair occupations. ↩
-
Standard mileage rates, Internal Revenue Service: 76 cents a mile from July 1, 2026. ↩
-
Publication 334, Tax Guide for Small Business, Internal Revenue Service, for use in preparing 2025 returns. See the Inventories section. ↩
