I would never suggest that a Vasectomy requires gneral anesthesia, not unless your surgeon is a total idiot.
A little pre-op valium and local anestetic makes it painless.
Mine took about 10 minutes, max. I had it done on a Friday, went home, sat on an ice bag for 24 hours and felt ready for work by Monday.
Now, maybe if your occupation is Cowboy, (Midnight or otherwise), Tour de France Rider,Pogo Stick Tester, Porn Star or something along those lines, you might need a few extra days off.