Modern Sails have 2 main enemies:
Flogging and Sun
When motoring the sails should be put away
Motor sailing is very hard on the sails. When the sails flog and beat against the rigging it breaks down the sail cloth causing them to become worn out sooner.
Cover the sails
UV rays are one of the most harmful things for a sail, new or old. Making sure there are no exposed areas of the sail sticking out of the cover is important. Having a good flake or furl makes this easier. Properly covering the sails can ensure a long happy sail life.
Use the appropriate amount of sail are for the wind speed
The windier it is the less area you need to make the boat perform at maximum efficiency. Reefing the main and furling the jib are the best way to reduce sail area. Strong winds stretch the sails causing the fibers to loose their shape and thus the sail to loose its shape sooner.
Halyard tension
Halyards should be tight enough to take the pressure off of the slides. It’s hard to make the halyard too tight- but when it’s too loose it puts pressure on the slides causing them to break. This not only effects the shape but how well the sails come up, down, and flake.