I have a 1989 535i bmw it may need upper controler ball joints how long should then be change?

Upper control arm ball joint??

Put the car on jacks and push the tire back and forth near the top of the tire. If there is a lot of movement then they need to be changed. Sometimes you can tell by looking at them. If they look bad or have a lot of ware then change them. If they were never changed then i would say then need to be changed...the car is 18 years old.