I have a 96 C 280 with 125K. Have changed the oil every 3.5 K and done all the regular maintenance. We have owned it since 50K. My question is....

With normal maintenance how many miles can i expect to get?

I am trying to decide when it will become too much to repair. i have already done a lot of bullsh** repairs to this car and am wondering at what point I should say enough. ANy thoughts would be appreciated - thanks in advance.