Where mid-sized fleets leak the most unnoticed money.
This is the longest chapter in the book and the one where a mid-sized fleet most consistently leaks money. Maintenance, tires, and parts are typically 8% to 14% of revenue — meaningful in absolute terms (for a $14 million fleet, that is $1.1M to $2M annually) but often mishandled because the line items are spread across many small transactions, multiple vendors, and several different inventory and expense categories that interact under IRC §471 and §263A.
Trucking maintenance spend falls into four categories that the books should track separately. Each has different tax treatment, different operational implications, and different opportunities for deduction acceleration.
Tires are the single most commonly mishandled area in mid-sized fleet books. The question is whether tires constitute inventory (capitalized to inventory, expensed via COGS as consumed) or current expense (deducted in the period purchased). For most mid-sized fleets at the $4M–$25M revenue range, the small-business taxpayer election under §1.162-3 is available and is the simpler treatment.
The fleet that consistently capitalizes major repairs as improvements is overpaying tax in the current year and recovering it slowly over the depreciation life. The fleet that consistently expenses repairs that should have been capitalized is creating an audit gateway. Working with a CPA who knows transportation specifically — and applying the §263(a) framework correctly — produces meaningfully better tax outcomes than the default "capitalize everything over $2,500" approach that generic accountants often apply.