Worrying about the value of the car can lead you down the wrong path. If you like the car and want to keep it, then it’s the replacement cost you need to think about. You’re not going to replace it with another old car with maintenance issues. You are going to pay more than what your car is worth to get a newer car. Newer car=more depreciation + more complexity. If you like the car, plan on spending on maintenance. No depreciation costs, no new car payments no sweating door dings.

When is it time to get rid of it?  When the body and subframe rot make the car unsafe.  All else can be replace.