I almost always carry a spare. I say almost because sometimes I forget or just get lazy when I'm just out paddling locally. It's a plastic straight blade that cost me around $16 at a local sporting goods store. The extra weight on a portage is insignificant, and there are times when I like using a straight blade vs. a bent shaft.

My bent shaft is that $40 plastic thing from Spring Creek, nice and solid, don't have to worry about busting it up on rocks. But it could happen, or I could lose it.

One time I almost needed a spare... I was fishing on Devil's Lake in ND two years ago in the spring, and anyone who's ever been there is probably familiar with how choppy that lake can get. Long story short, the wind picked up when I was ~1/2 mile offshore jigging a walleye reef, and I stupidly had the straight paddle just sitting on the gunwale and cross beam in front of me. Chop picked up, paddle went overboard and started drifting away fast, lucky I had a line in the water and I was able to quickly wrap it around the paddle shaft and pull it back to me.

I would have been in a bad spot right there, as the wind was blowing off shore at a pretty good clip. I would have drifted out into the big open water and had no good way to align myself against the increasing waves. Temps were probably in the mid 30's that morning too... wasn't too long after ice-out (ND doesn't close fishing seasons like MN does).