Its an eternal question which strategy is best, Run a car into the ground, or replace it regularly. No one so far has come up with a particular fault that finishes them off at such and such a mileage. Selling just before its due an expensive service , or tyres need replacing etc can make sense if you are thinking of selling anyway. But oherwise its a choice between keeping the devil you know, and expect to spend some money on repairs, ( or not if you are lucky) or trade in regularly and expect to lose more money on depreciation.And might still be unlucky on repair costs. You win some, you lose some. With good maintenance you win more often.
One possible guide is how many miles are covered on warranty. Makers wont normally cover 100K miles if they know too many things start to go wrong by 60K for instance. But there are good miles and bad miles. A car is more likely to reach 100K without problem if it gets lots of long journeys with warm oil , than one that does only a few miles once a week. And if you only do a few miles, the age depreciation per mile driven is massive on a newer car.
And of course many a car with perfect mechanics ends up being scrapped because of rust.
its nice to have a newer car but it can be an expensive and unnecessary luxury , Or is it ?
I kept my Yaris 14 years from new . And sold it before any major mechanical repairs or rust. Win. It became almost a disposable car. Any major repair required I might just scrap it. I only sold it because I wanted a mk4 Jazz. Now got a taste for new fangled cars,and probably wont keep it 14 years. But you never know.