Oil and filter intervals: how to decide in real life

“The factory says 30,000 km” doesn’t mean it’s best for your engine. That number is often about stretched service plans, not long-term wear. Oil life depends mostly on how you drive, not what a brochure claims.

What destroys oil the fastest

• Short trips + cold starts (oil doesn’t reach stable temperature)
• City traffic (idling, heat, constant load changes)
• Turbo + heavy use (more heat, higher demands on oil)
• Diesel + DPF regenerations (in some cars fuel can dilute the oil)

If any of this matches your driving, you’re effectively in “severe use” — and your interval should be shorter.

A simple rule that works for most cars

• Minimum: once per year (even with low mileage)
• Normal use: be reasonable — don’t chase the absolute maximum interval
• Severe use (city + short trips): shorten the interval because oil ages faster

I’m not giving one “magic mileage number” because it depends on the car and usage. But if you do lots of short trips and stretch intervals to the limit, you’re simply wearing the engine faster. Period.

Filters: don’t ignore the basics

• Oil filter: always with the oil
• Air filter: affects engine health and fuel economy
• Cabin filter: comfort and clear windows
• Fuel filter (especially diesel): many people leave it too long

Don’t use random oil

Don’t pick oil like “5W-30 is 5W-30”. The wrong spec is risk. Follow the manufacturer-required specification — that matters more than the viscosity label alone.

When selling: an oil invoice is cheap proof that works

An oil and filter invoice is one of the simplest signals that the car was cared for. Date + mileage + proof means fewer questions and less price haggling.