Laminated string sails can suffer in various ways aside from the usual UV aging damage or abrasion -
Mildew can grow between the layers of cloth and cause stains that won’t come out. Repeated flexing or folding in the same spots can break down the cloth. If they applied surface tapes made of carbon or high modulus fiber the adhesive can break down and the tapes can delaminate.
That said, they have no significant stretch and will hold their shape better than traditional Dacron sails and can be made lighter for a given strength. They should last 7-10 years depending on your use and care.
That’s about as long as anything soft on a boat lasts