I have a four mile commute. Not too long ago I picked up a goat head on the way in and didn't know it until I took my bike out of the rack at work. The only thing on me at the time was my frame pump. I had to stop every 3/4 mile and pump up the tire. I carry a spare tube now but it might have taken me longer to fix the flat than to stop and add air on the way home. With the fast leak a C02 inflator wouldn't have helped much unless I had a box of cartridges with me.