how often do they have to be replaced. on 1995 Pontiac Bonneville

the city i live in does have bad roads, and i try to go around the potholes, some are hard to though. i just had mine done last summer, and now i hear them ride isnt as smoothe as it was wen i got them done last year.

Asked by for the 1995 Pontiac Bonneville
What exactly needs to be replaced? The struts (shock absorbers) tires or suspension componets/bushings? More info. needed!