I guess it depends on time, a 2 year old car with 5,000 miles on it isn't likely to play up and has every chance of being reliable.
A much older car say 17 years old for example with sub 30,000 will probably suffer from seal failure and be costly to get relabel, however once there should cause no further issues
Being in frequent and regular use with similar maintenance are
FAR more important than low mileage. A few years back, my sister bought a 35 year old car with a genuine 18,000 miles and I followed with a slightly newer car with about 60,000. Both needed complete hydraulic rebuilds, new tyres, various bearings, hoses, wiring and other fettling before being used daily for several years. Newer cars are even worse for electrical faults, as they don't suffer from the atrocious Lucas connectors and inadequate earthing that are the real problem of
The Prince of Darkness. Modern cars don't allow for the simple cleaning/tightening up/replacement of the connectors, and welding a cheap M6 bolt(as a dedicated earth) to the bodywork near the electrical units that has never failed to eliminate problems for me, so you actually have to do some real work to fix the faults.