Tim, hit it on the head. Heat probably is the biggest destroyer of tippet (actually any mono line – i.e. includes leaders too). If tippet is kept out of the sun or heat it can last a long time. The “fresh” tippet idea isn’t as true as some fly fishers believe. But if you don’t fish a lot then get the smaller spools of tippet not the guide size. If your tippet seems to break too often then check your knots, that’s probably the culprit more than the tippet being old. Remember always, always wet or spit on your knots before tightening them. They should slide tight.
Almost forgot – 7x tippet??? be very careful on hook set. 😉
