Certain things / repairs com up at certain mileages. Things like, timing-belt/chain, water pump, gear fluid change, brakes, clutch, shocks and control arms etc. are all affected by mileage and accumulate to a good deal of maintenance costs

Also some components are only designed for a certain lifetime. But that largely depends on the car. For example a certain models automatic transmission may only be designed to last 200k miles. This is something that can be repaired, but usually it is not economically viable to do so.

It is important to look at the specific model to decide if 90k miles is already a lot or nothing at all.

What you also want to consider is, that a car wit very low mileage for its age surly did either stand around a lot or was used mainly for really short trips. Especially short trips wear down the motor much faster, because it never gets a chance to get warmed up properly. Lubrication etc. does not work as well as long as the car is cold.

Certain things / repairs com up at certain mileages. Things like, timing-belt/chain, water pump, gear fluid change, brakes, clutch, shocks and control arms etc. are all affected by mileage and accumulate to a good deal of maintenance costs

Also some components are only designed for a certain lifetime. But that largely depends on the car. For example on certain models the automatic transmission may only be designed to last 200k miles. This is some thing that can be repaired, but usually it is not economically viable to do so.

It is important to look at the specific model to decide if 90k miles is already a lot or nothing at all.

What you also want to consider is, that a car with very low mileage for its age surly did either stand around a lot or was used mainly for really short trips. Especially short trips wear down the motor much faster, because it never gets a chance to get warmed up properly. Lubrication etc. does not work as well as long as the car is cold.