While I went 4 years without a flat, my luck ran out with a big blowout on a group ride in the middle of rural Maryland a few years ago. The tire was blown, so someone in the group had to ride back to his car to pick me up. I did not carry and extra tire with me, just a couple of tubes.

I've had gradual flats, too. The best thing you can do is pump your tires to the proper pressure before every ride. That will decrease the likelihood of getting pinch flats, which result from too little air.

Except for blowouts, which you cannot miss, you might feel like you're dragging something, or that your legs are really heavy.

Practice changing flats in your house; you'll be glad you did when you do get one on the road.