Hi Waggles, I got back into windsurfing and got KA sails in 2001, and am only just replacing some of them due to wear and tear - that's a pretty good life span. I have noticed that some of my newer sails (KA and Aerotech) have better (stronger) construction, have a more stable centre of effort, and a better wind range. However I am also enjoying using a couple of my old KA sails which I've only recently discovered how to rig properly, like my circa 2001 KA Kruze 5.8 - I used to think this sail was pretty ordinary, but have recently discovered the correct amount of downhaul / outhaul to use and it's as good as my modern sails when rigged right. I'd keep using your old sail until you're feeling it's holding your sailing development back, by then you'll be ready for newer gear. Release your urge to spend $$$ on your girlfriend, and when you're ready to buy new gear she won't complain.