>> On every change, put a drop of oil on a piece of glass and check it under a
>> $2 10x eye loupe in strong light. You can easily see metal fines in the oil,
>> most of which are normal. You can determine if they're ferrous or
>> non-ferrous by passing a magnet underneath the oil drop. If you see larger
>> particles than normal, better get it checked out.
I've owned many cars over the years. I've never experienced oil-related failure.
I think the only engine ( block ) failure was a blown head-gasket.
I would see more of a general breakdown; radiator, water pump, air-conditioner, fuel injectors, generators, transmission, etc. etc.
At some point, you get tired of; the unreliability or the $200 visits to the garage.