I will be the only one to share a different view here then
Higher mileage and well maintained.? OK that will protect some things, but not everything. Various mechanical components have a life span. some cannot be maintained and some lifespans can not be increased with regular maintenance.
Ball joints bushes and bearings wear, water pumps, shock absorbers, and a lot of other things do not benefit from a service
Now you could go for a mileage around or below when they are due first replacement, (maybe 70-80k?) so expense could be imminent, or a mileage where they should have been replaced once already.
They may well have been replaced, but that also depends on the quality of the replacements.
My 1 Series has just had an MOT yesterday. however last week I had a look around to see if it needed anything doing so I jacked it up
One rear shock absorber was leaking, so I ordered two new ones.
On replacing them I found that the 'still good' shock absorber was an original, still badged with the BMW sticker
The leaking one however was a replacement and a name I had not heard off
Now the car has done only 56,000 miles, would you expect it to be on a third shocker?
I also had to change a track rod end ball joint and a steering arm , Both had already been replaced .....with cheapo stuff.
Even electrics suffer with age, the lamps get dimmer, dashboard instrument cluster, outside lamps, all will help the car look a bit tired, Sure they can be changed but less likely to require it on a low mileage.
Bodywork will have more chips and marks that cannot be helped, seats will show more wear, steering wheels will be a bit more worn. All can be maintained but at a cost not necessarily needed yet on a lower mileage.
So a higher mileage HAS to show a good price to allow for stuff that is still due to fail
The rate of requiring stuff goes up exponentially as more things reach their lifespan. its not linear.
Maintenance, (where you can) just means you get the maximum out of it, but it still wears, and fails eventually.
Most things that people are having to change on here are items that cannot be maintained, not engines, gearboxes and differentials that see the affect of good or bad maintenance.
We are all doing bushes, suspension, brakes, water pumps, thermostats, radiators etc etc no amount of looking after the car affects them.