Well, I use 20/24 spoke count wheels commuting, taking the same bike out for training and longer rides. But repairing them on commutes isn't my main angle. I was more interested in storing spokes where I know I can find them immediately, and the prospect of repairing on the road is a side benefit. If I need a spoke wrench I know that it's on the bike, so why not the spoke?

The last time I broke a spoke on my 36 spoke wheel I didn't even need to true it to get home. I rode it several days in fact, until I got a replacement from the LBS.

The fiber-fix emergency spoke that TJspiel mentioned is a much more rational way of preparing for broken spokes however.