While it is not used, it is still 7 years old and everything ages over time. The price is not that much of a discount of buying brand new. Offer them half price on the brand new sail ~$285-$300
it depends alot on how it was stored, 7 years won't do that much harm if it is stored in the right conditions, (cool, dry and dark) if it was exposed to the elements it might not be in such good condition