I found the key is to start with a new chain. Keep it sharp and well lubed. If you let it dull, or get low on lube, the chain will overheat. Once it overheats, it affects the heat treatment of the chain itself. Then it will not hold an edge when sharpened, and it will tend to stretch more.
When I put a new bar on my Husky, I got three chains. I rotate them out as soon as they start to dull.
By doing this, I do not stress the chain as much. It is easier to "touch up" the chain with a file if you do not really wear the tooth edge down. It does not overhaet the chain. And, with three chains, if something happens when I'm out in the woods, I can continue. With only one chain, you might be finished for the day if you throw a chain or catch a rock.