740ilsamue

I could really use some help with my head lights. Several months ago, the driver side headlight needed to be replaced, and ever since replacing both with Phillips oems I bought from Rockford online, both take turns not working. Sometimes weeks go by with one side not working, then they switch. Have I bought defective's, or am I missing something? Both costs around $160, so I didn't go cheap. I can't seem to find a thread covering this problem, so any help would be cool.