When does a car stop being worth using for gig work?

Two forces moving in opposite directions

As a vehicle gets older and racks up miles, depreciation and financing cost per mile generally fall — often steeply once a loan is paid off, since a paid-off car has no monthly payment eating into cost per mile at all. That's a large part of why real cost-per-mile notes that "an older paid-off car has far less depreciation and no finance charge, and its true cost per mile can be substantially lower."

But the same page adds the honest caveat: "though maintenance rises." Repair frequency climbs, parts and labor cost more as a car ages out of routine service, and the risk of a single expensive breakdown — a transmission, an engine, a major electrical fault — grows. For a while, the falling side (depreciation) dominates and total cost per mile keeps dropping as the car ages. Eventually, for some vehicles, the rising side (maintenance and repair risk) catches up and cost per mile starts climbing again.

The signal is the number, not the odometer

Because these two forces trade off differently for every vehicle — depending on make, how it was maintained, how it's driven, and local repair costs — there's no universal mileage or age where the crossover happens. The useful move is to periodically recompute your actual cost per mile using the method on real cost-per-mile, and watch the trend rather than reacting to a single bad repair bill or a round-number odometer reading.

Compare that recomputed number against your own break-even hourly rate. If your cost per mile has been climbing for a few consecutive recalculations and your break-even rate is creeping close to — or past — what typical offers in your market actually pay, that's the real signal, not a specific mileage threshold some article names.

The resale-value cliff is often the concrete trigger

In practice, the moment that actually forces the decision is usually a single event rather than a slow drift: a repair estimate that costs more than the car itself is currently worth. A $3,000 transmission quote on a vehicle worth $4,000 used is a much sharper signal than a mileage number, because it's the point where continuing to drive the car for gig work means betting real money against an asset that can no longer absorb the loss if something else breaks soon after.

Three paths once the numbers turn against you

• Keep the car, drop it from gig work. If your recomputed cost per mile no longer clears your break-even hourly rate but the car still works fine for personal driving, the simplest move is to stop putting gig miles on it rather than replace it outright.
• Replace it. Run the same cost-per-mile method on a realistic replacement — including its own financing and insurance costs, not just a sticker price — before assuming a newer car is automatically the cheaper option per mile. A newer vehicle resets the depreciation clock, which can raise cost per mile in the near term even as it lowers maintenance risk.
• Stop gig driving on this vehicle strategy altogether. If no vehicle you can reasonably afford — the current one or a replacement — clears your break-even hourly rate against what offers actually pay in your market, that's a real answer, not a failure to find the right car.

None of these is right in general; each depends on your own recomputed numbers, which is the entire point of tracking cost per mile as an ongoing habit rather than a one-time calculation.