Should maintenance be performed by mileage or time?

Quick facts

  • Oil degrades from heat cycles even without high mileage. Time matters as much as miles.
  • Vehicles driven mostly short trips accumulate engine wear faster per mile than highway driving
  • "Severe duty" schedules apply to most city driving, towing, and stop-and-go commutes
  • Cabin air filters and tire rotations follow mileage primarily, not time

Maintenance services are usually recommended either by mileage or time.  The last several articles I have mentioned that time and time again.  We will use oil changes as an example to be performed every 3 months of 3,000 miles.  So which is it?  Time or mileage?

Most people average 15,000 miles a year and now since the Covid-19 Pandemic the average person is now driving a lot less.  The statistics from US Dept of Transportation shows that based on the first half of 2020 at least 20% less.  So the quick answer would be whichever comes first, the time or the mileage.

The less you drive your vehicle the more extreme driving conditions your vehicle is facing.  The more extreme the driving conditions the more often it needs service.  Fluids, rubber, gaskets and seals can deteriorate by time and lack of use.  Not driving a car long enough to warm up properly, or to get the fuel system cleaned out by driving at a freeway speed, or to keep the seals and gaskets lubricated with circulating fluids can cause further issues.  Seals and gaskets that are not lubricated will become dry then they shrink and crack, this can cause leaks.  The fluids can also break down and not do the job of lubricating, cleaning and conditioning of the system they are designed to work in.

If you want to keep your vehicle in tip top shape, maintain it, take care of issues when they are small and follow the mileage or time whichever comes first motto.  Happy Motoring!

Frequently asked questions

Common questions

If I only drive 5,000 miles a year, do I still need to change my oil twice a year?

Yes, in most cases. Engine oil breaks down from heat and combustion byproducts regardless of mileage. Most manufacturers and technicians recommend changing oil at least once a year even if the mileage interval has not been reached. Short trips are especially hard on oil because the engine never fully warms up to burn off moisture and fuel dilution.

What counts as severe duty driving?

Severe duty conditions include frequent short trips under 5 miles, driving in extreme heat or cold, towing or hauling, driving in dusty or dirty conditions, and extended idling. Most city commuters qualify as severe duty even if the driving feels routine. Severe duty schedules call for more frequent service intervals than the standard recommendation.

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