I got my first two flats in a year of riding on two consecutive days last week. Luckily, because of where they occurred (& b/c the first ended up being a slow leak instead of an instant flat), I was able to change both at home.

I had witnessed tire-changing before so I knew what I had to do... But the first one still took me a really long time. The second one took me less than half the time of the first... and I feel much better about what would happen if I had to fix a flat on the road.

It was really stupid things that made the first change take such a long time -- like me being really uncoordinated when trying to figure out how to deal with getting the chain back on the cassette at the same time as slipping the dropouts back onto the wheel -- once you've done this once though, you know how to do it and it's a cinch (well maybe it is the first time for some people, but... ).

One recommendation -- don't use ultralight tubes the first time you attempt to change a tire, especially if your tires have a stiff bead. It's easy to pinch them during installation.