Tough question
If all you plan to do is cruise and the sail is structurally ok then you should be fine. Otherwise, if you want the best performance then a new sail is in order. That being said, your boat is mainly headsail driven as is my Ericson 35. I have a new headsail and an old main and I am still winning races. If you decide to buy new, find a good local sailmaker who will come down to the boat and take measurements and then stand behind his work. I was not satisfied with the cut of my Genny last season so my sailmaker came out sailing with me and he agreed. He recut it free of charge.You should also check out this site for Ericson material:www.ericsonyachts.org