They lose their ability to hold their "shape" and become less efficient. This is primarily a concern for people that want to go as fast as possible. I've been p

They lose their ability to hold their "shape" and become less efficient. This is primarily a concern for people that want to go as fast as possible. I've been perfectly happy with sails after 20 years of light use. I mean, I can see that they don't really have the best shape, but I'm still sailing so all is good.