You probably don’t need to change your oil as often as you are, if it’s registering as an expense at all.
Check what the manufacturer actually says - for example my manufacturer says don’t bother changing for two years. Lots of Americans driving the exact same cars change their oil every three months for no reason.
Actually this is exactly about expenses you are not consciously "registering", but they are real, and they add up. A daily coffee is not "registering" as well, but it's massive amount of money if you consider how much you spent in a year.
Would you mind quantifying how the coffee argument applies to this discussion, which is about oil change?
For example, here in the UK the average cost of oil and filter change (if you pay someone to do it rather than doing it yourself) is £102 [1]. Done every other year, this amounts to £51 p.a., which is less than a typical tank of fuel [2].
You probably don’t need to change your oil as often as you are, if it’s registering as an expense at all.
Check what the manufacturer actually says - for example my manufacturer says don’t bother changing for two years. Lots of Americans driving the exact same cars change their oil every three months for no reason.