Oil changes are often done on a calendar, but condition-based decisions can reduce cost while improving reliability—when done correctly.
Time-based oil changes
Pros: simple, predictable
Cons: can waste good oil or miss early degradation
Condition-based oil changes
Driven by indicators such as:
- viscosity trend
- oxidation level
- water content
- particle count / cleanliness
- additive depletion markers (as applicable)
A hybrid strategy works best
Use time as a maximum limit, but allow earlier changes if condition shows risk.
Summary
Change oil when it’s no longer fit for purpose, not just when the calendar says so. The key is consistent sampling and trending.