I do that anyway, if it's raining or snowing I'll swap the tube and patch it later when I'm home and dry.

I've had one flat in the last year and it was in the middle of winter... steel wire that I caught with my finger. There's no goatheads or anything like that around here so staying away from the curb seems to keep me flat-free. I have gatorskins, marathons and some conti sports tires that I ride and they all seem dandy.