When you're starting out, I cannot emphasize the importance of building that core act. You should do it constantly, revise, refine and polish. Add act-outs, tags and toppers. Until it crushes. Worrying about your friends hearing the same jokes is counter-productive to you really developing and polishing your act. Not to mention that it can have a cascading negative impact on your development.
Comedy's Dead! Yeah, I heard that from some young comedian the other day. Well don't tell that to Al Martin, owner of the New York Comedy Club and The Broadway Comedy
One of the biggest complaints I receive from comics and students trying to get mic time is that "everything seems to be a bringer show." Several of my students "burned out"