An ideal high mileage vehicle would be single owner, not too old, mostly highway mileage, with good maintenance records. Age eventually kills everything. I've seen Honda Odyssey's go for 500K+. You want the salesman's car who covered hundreds of miles a day, or someone with an exceptionally long highway commute.
Back in the day, we'd get 2-3 yr old cars with just over 100K, and they looked nearly new.
This.
Cars age just like humans: as an indicator of health, how many years you've already spent on earth is less important than how you have spent them (octogenarians aside). At my old place of work I had a co-worker that every new young male employee would try to flirt with. (For the record: I did not, because I was already married and my wife would have killed me.) She was in her early fifties! But she was fitter and looked better than 90% of the staff, including the girls in their twenties and early 30s. Her secret: she had never smoked, drank alcohol only very rarely and in very sensible amounts, ate healthy with lots of vegetables and fruits and sufficient protein; she commuted to the office by bike, worked out in the gym regularly and practiced yoga daily.
Looks aside, she also was an absolute tank. The amount of work she did - and did well, and the success she had in bullying other people to get their **** together (read: the art of project management...) - was phenomenal. Nobody ever believed her when she told her true age.
Take care of yourself, and chances of staying in a presentable shape and of preserving your mental and physical performance are much higher than you think.
And the same is true for cars. I've experienced a lot of high-mileage cars that drove absolutely fine and were ridiculously reliable. I've seen engines open after 400,000km that were exceptionally clean and whose wear measured within tolerances for a new engine. I've also seen engines completely sludged up at less than 100.000km, with seized camshafts, worn bearings, worn cylinder liners etc.
How a car is driven and how it is treated is much more important than how many miles it has run. Also keep in mind that a lot of things fail not with mileage, but with age - or heat cycles. After 20 years, chassis bushings and rubber hoses on a low-mileage car will be as brittle as in a high-mileage car that has covered double, triple, quadruple the distance. In not to few cases, these parts in the high-mileage car will actually be better, because they already have been replaced at least once.
Thus, I do not care about mileage at all when buying a car. I care about a car's history and about it's current condition. The number on the odometer may offer some hints in thus regard, but that's about it.
