Ok, I'm super anal. I asked for the responses back 12 weeks before our wedding. I figured that we'd already sent STD's a year in advance. Most people knew if they were planning on taking vacation time, buying plane tickets, etc. 3 months before our wedding. Of course, we had stragglers. We didn't get a true guest list estimate until mid September. Since the RSVP date had passed, the stragglers felt guilty. I'd say it worked out for us.