It's very random, I got rid of the two Xantias both had done 124k miles. On one of them the engine clattered like anything and used stupid amounts of oil but the rest of the car was fine (despite the fact I think I might have topped up the suspension fluid with miracle grow), the other one the engine was still very strong, but everything else was naff.
In the end I got rid of them both.
My folks got 170k out of a 1.3 Astra many moons ago and 250k (actually more then that, it was 250k when he bought it) from a Pug 505, probably would have gone on a bit longer, but my dad decided getting the cam change was a low priority.