94 GA GT headlights go out....

Coming home the other night we started out and the headlights were working. When we destinated both headlights were out, hit the highbeams and they work fine. Tap the lenses and they come on, but it seems they are getting worse over time. Over time seems like I have replaced them from time to time, not like the daytime running lamps though(horrible!!). Any suggestions on the headlights would be appreciated.