I am my own mechanic do all my own work. I live in the flatlands that has a bit to do with chainlife and I do not normally ride in the rain so that has something to do with it. But the one thing also that helps is I keep the chain clean and well lubed. I use a wipperman connex so I can simply take chain off and wipe it down with OMS then re-lube. I am not anal or spend huge amounts of time with this but I easily get 5-6000 miles on a chain. Frankly I could get more I do not change them when they are at any specific stretch. I do not use chain checking tools, I use a good steel ruler line up pins. My present chain on the motobecane has 6000 miles and no real stretch less than 1/32 of an inch. Shifts perfect but I will probably change in in about 500 miles chains are not that expenses.