Decided to replace
I just replaced the sails on my '79 Oday 23. Like yours, they were the original Neil Pryde deal. No rips, tears or stains; in other words, no "need" for replacement. However, I am very glad I bought new sails. As good as Sailcare may be (I have no experience with them), your sails will not come back functioning any better than they did before; they may look better, they may not have the holes, tears or unravelling seams, but they will still be the same blown-out, shapeless things they were before you shipped them off. I can't get over how much difference the new sails make on my boat. I can point so much higher and go so much faster it seems almost like a different boat. If you can afford it, go for new sails.