I tend to use 3 chains a year, I like to use a new one (and maybe w/ new cassette) in the summer when it's nice out (historically July but this year since May), when that chain is stretched out, in the fall sometime, I will replace it, and I always hope that chain will make it through the rainy gritty winter but it never happens. And the next chain wears fast too so that it's unpleasant enough that I want a new one for the summer.