More in lighter winds, but I've noticed it in moderate winds as well.
Spin is an '08 so more on the full side. It was in great shape when I got it. I don't sail that much. Around 4 days a month from May - Sept. How can you tell if it is time for a new one.
By 08 they were the flatter cuts.
Look at your luff tension, it should be 45-90 degrees at most on the twist grab.
Also if you have never done anything with it, look at the luff tension line. This should be tied about 1/2" tighter then the sail luff itself. This line sometimes has a big effect on flying the spin in certain conditions.
