i've experienced the same thing. every track i write sounds better than the last, so as time goes by, instead of accumulating a bigger and bigger pile of techno i can play out, i'm always in a state of having one track i'm happy with, and needing to come up with 10 more.

last time i played my live pa i ended up spending the last 3 weeks before the show frantically remixing all my old tracks because i didn't think they sounded good enough to play in the same set as my newer material. it was a lot of work, drove me bananas, and made me cautious about accepting any more live pa gigs.

but i just plod on in the belief that as i get more experience on the production end, i'll eventually have a more consistent sound and throwing together a live set will be much less painful.