I guess two years will not be a problem but I want at least 6
Take a look at the sails of the Vendee Globe boats: The pictures I have seen of the mains show sails in pretty bad shape. Sure they maintain the shape but you can see delamination. I guess a Vendee Globe worth for about 3 years in what regards the use I give them, but not in what regards folding.
The real problem with laminated sails is when you fold them on the lazy bag and most of all when you reef them. They hate to be folded and they can sustain a limited number of folds before start to delaminate.
On the vendee globe they have the big advantage of having the sails always up and never on a lazy bag, except when reefed.
I confess I don't know much about the subject but a long talk with the owner of Speedsails (Miro) was very instructive. He sure knows a lot more than me
I wanted to have performance sails, he is a specialist in laminated sails and even so he advised me against after inquiring about how much time I sail.
He said that if I really wanted the extra performance the best choice was the type of sails I had on the Bavaria, Sandwich sails (expensive sails). He makes them too but even so he says that nothing is as durable as a good Dracon sail. Have a look at his sandwich sails:
go to randa (mainsail), then to Randa structure cruising and then download " visualizza la Brochure" (download)
If you cannot find anybody that can deal with you on a personal basis and that you fell that can give you good advise, I will give you Miro's telephone number and I am sure that a good talk with him will put you on the right track. At least you will understand clearly what are the different options. He speaks very good English, I am sure he knows perfectly what he is talking about and he is honest.