The cheapest truck is rarely the new one or the old one — it's the one you sell at the right time.
Running a tractor to 1.2M miles to 'get value out of it' usually loses money once R&M crosses the depreciation curve. Trading every 3 years often overpays depreciation. The sweet spot is data-driven.
Plot monthly cost = depreciation + R&M + downtime cost. Depreciation falls sharply, R&M rises slowly until ~500K mi then steepens. The minimum of the curve = optimal trade point. For most OTR fleets this lands at 500–650K miles or 48–60 months.
Common-spec tractors (13L engine, 10-speed AMT, fleet color, popular axle ratio) hold value 10–15% better at trade. Bespoke specs save fuel but cost on resale — model the whole curve.
Full-service lease (Penske, Ryder) trades CapEx for predictable OpEx and shifts maintenance risk. Cheaper in years 4–6 of a unit's life, more expensive in years 1–3. Best for fleets that can't predict cash flow or service load.
Sell when monthly R&M cost approaches monthly depreciation of a replacement. For most OTR, that's 500–650K mi.
Total cost is usually higher, but cash flow is steadier and maintenance risk is offloaded. Best for fleets without strong CapEx access or in-house shop capability.