1993 Volvo 850 Constantly breaking down

Transmission problem
1993 Volvo 850 4 cyl Two Wheel Drive Automatic

HI
Our Volvo has been a bottomless pit of repairs. It has had a complete valve, fuel injectors, fuel pump. Now it needs another fuel pump and possibly needs transmission work. When do we cut our losses and stop putting money into this car? Or is it worth investing even more money? Is is commom to have the fuel pump go out again in just 2 yrs?