Starter problem 1991 honda accord

I have a 1991 honda accord. I have replaced the starter 3 times. Each starter last about 6 months before it starts to have problems. When I replace it the car runs like its brand new for about 6 months then starts intermittantly until I finally replace it. Does anybody have any Idea, Can it be something that makes the starter go or am I just having bad luck with starters. The first one came from the junk yard "understandable" the last two were rebuilt from an auto parts store.