My recent flats have been puncture flats from debris. I've decided I'm just going to get a couple of new tubes and go on. The tubes with punctures I might patch, but they are more than a couple of years old and it might be worthwhile to just spend a few bucks on new ones. I might put a slime tube on the back, since that one is such a pain to change. I rode casually for three or four years without a single flat, and this year I've had several. Maybe it's just because I'm riding more. I have new tires this year, so that can't be the problem. But, I will never get past the "newbie" stage if I don't learn some of this stuff. This forum has been a great help! Thanks to everyone who posts. They have made me think about stuff I didn't know I needed to think about! :-)