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A contractor signs for a new dump trailer on December 22 and pays a deposit. The dealer confirms a February build slot. The deduction behind that decision lands in the following tax year, because the test for Section 179 is not when you bought the trailer. The test is when it was ready to work.
Section 179 is part of the Internal Revenue Code, the federal tax law (26 U.S.C. § 179). It lets a business deduct the cost of qualifying equipment in the year it is placed in service. Ordinary depreciation spreads that cost over several years instead. Section 179 is an election, not a requirement: you choose it on your federal return, and the IRS administers it. Bonus depreciation is the special depreciation allowance in section 168(k) of the same Code, and it applies to qualifying property automatically unless you elect out.
Both of the tools worth knowing here — Section 179 and 100% bonus depreciation — hang on the same phrase, and it is the one most likely to be misread at the end of December. What follows is what the phrase means, how the two tools differ, and the vehicle rule that quietly decides how much of a truck you can actually write off. For what is deductible in the first place, rather than when, start with our US contractor write-off list.
What “placed in service” actually means
The IRS test is availability, not use. Property is placed in service “when it is ready and available for a specific use” — which means a compressor sitting in the shop, wired and working, counts from the day it was ready, even if the first job it runs is in March. It also means the opposite: equipment still on a truck somewhere, or a machine delivered but awaiting an electrician, is not placed in service until it is ready to go.
Three consequences follow, and they are the practical ones.
Paying does not do it. A December payment on something that arrives in February buys you a February deduction. Ordering does not do it either, and nor does a signed purchase agreement. Financing, on the other hand, gets in the way of nothing. An asset delivered and ready in December counts from December, whether you paid cash, used a loan, or spread it over five years. The deduction follows the asset, not the money.
Which makes late December a delivery problem rather than a buying problem. If the deduction is the reason for the purchase, the question to ask the supplier is not “can I order it this year” but “will it be here, and working, before the year ends.”
Section 179 and bonus depreciation are two tools, not one
Section 179 and bonus depreciation are often spoken about as if they were the same election. They behave differently in ways that matter to a small trade business.
| Section 179 | 100% bonus depreciation | |
|---|---|---|
| Ceiling for tax years beginning in 2026 | $2,560,000 | No dollar ceiling |
| Phase-out | Reduces once section 179 property placed in service in the year exceeds $4,090,000 | None |
| Can it create a loss? | No — limited to taxable income from your businesses, with the excess carried forward | Yes |
| Choose asset by asset? | Yes | Applies by class, unless you elect out |
The taxable-income limitation is the line that catches owner-operators. Section 179 cannot take your business income below zero; the disallowed amount carries forward instead of disappearing, but it does not land this year. Bonus depreciation has no such limit and can create a loss. The 100% rate applies to qualifying property acquired and placed in service after January 19, 2025, and is no longer on a phase-down schedule, though you can elect a lower rate if a loss is not what you want.
That is worth thinking about in a thin year. A large deduction against a small profit is not obviously a win, and a deduction taken now is one you cannot take later.
The Section 179 vehicle rules, and the six-foot bed
Work vehicles have their own ceiling, and the popular version of this rule — buy anything over 6,000 pounds and write off the lot — is wrong often enough to be expensive.
Above 6,000 pounds gross vehicle weight rating, a vehicle escapes the depreciation caps that apply to ordinary passenger automobiles. But sport utility vehicles in that range carry their own Section 179 ceiling, $32,000 for tax years beginning in 2026. The federal definition then excludes some vehicles from being treated as an SUV at all, and the exclusion that matters on a job site is this: a vehicle with a cargo area of at least six feet of interior length that is not readily accessible directly from the passenger compartment.
In plain terms, the bed length decides it. A crew cab with a five-and-a-half-foot bed is an SUV for this rule and meets the $32,000 ceiling. The same truck specified with a six-and-a-half-foot bed is not, and Section 179 applies without that cap. A cargo van with no seating behind the driver falls outside the SUV definition on a related test.
Bonus depreciation is not subject to that Section 179 SUV ceiling, so the two often work together on a heavy vehicle rather than one replacing the other. Which combination is right depends on your income for the year, and it is a conversation to have with your own preparer before you sign, not after.
Business use is a condition, not a formality
Both tools only reach the business-use share. A truck used 80% for work supports 80% of the cost, and the split has to be supportable — which in practice means a mileage record kept as you go rather than reconstructed from memory in April.
The condition continues after the year of purchase. Should business use later fall below the required level, you recapture part of the deduction and it returns as income that year. Picture a truck bought for a commercial contract that ends in eighteen months, after which it mostly sits. That is the shape of purchase where recapture bites.
The case for waiting
There is a version of this decision where January is the better answer, and it deserves saying in an article that otherwise reads like a countdown.
Start with the profit. A modest year now and a stronger one expected next both point the same way: the deduction buys more against the larger income. Then there is equipment you had not already decided to buy. The tax saving covers a fraction of the cost, so the purchase still takes money out. Cash timing matters too. A December delivery pulls the payment schedule forward for a benefit that waits until filing. And when the asset cannot be ready before the year ends, the calendar has already decided for you.
One knock-on is worth planning for either way: a large deduction changes what you owe, which changes what your quarterly estimated payments should look like. Better to adjust the January payment deliberately than to discover the overpayment at filing.
One more boundary. Several states do not follow the federal treatment of bonus depreciation, and some cap Section 179 well below the federal figure, so the state result can differ from the federal one on the same purchase. That is a question for your preparer with your state named, not something to assume either way.
Where that leaves the decision
A signature in the last week of December does not buy the deduction. An asset earns it — in your hands, ready to work before the year ends, used mostly for the business, and bought for a reason that survives the tax saving turning out smaller than you hoped. If the trailer arrives in February, so does the deduction. The rest of the decision is simply whether you needed the trailer.
ON A DECEMBER DECISION WITH NO NUMBERS
Knowing what the year actually earned is what turns a purchase into a decision.
Whether a deduction helps this year or next depends on a profit figure most operators do not have in front of them in December. SendWork keeps the jobs, quotes and invoices in one place as the work happens, so the year to date is something you can look at before the dealer needs an answer.
