I have the above car with 200,000 miles on it.

I have the above car with 200,000 miles on it and I am concerned that I am about to spend big dollars on repairs, so I think I am going to trade it in. Has had all regular service and is due for one now. Needs buzzer for rear sesnor replaced, auto window up/down on driver door and is using more oil. Engine light has been on for a year, dealer tells me it is an oxygen sensor and that it can be fixed by them going in a cleaning the valves or something. Also, just recently started to have issues starting, when I start it the entire engine/car will shake and seems like it is not going to start. Once it starts, the remainder of the day it is like a new car. Yesterday, it took forever to start and then this morning no issure or hesitation at all. Starting to have some exterior door trim rust causing the trim to pull away. Otherwise, car runs great and looks like new. What can I expect? Should I dump it or keep it and run the risk of major issues? Any thoughts or advice?