In my limited experience when a chain starts stretching at a rapid rate it is close to the end of its lifespan and nothing you can do will save it. What's more, continued use may wear out front and/or rear sprockets, and this can disable your bike even faster than the chain itself.
A good chain, on the other hand, rarely seems to need adjusting (if an o-ring or x-ring it doesn't even need lube--merely cleaning after significant exposure to water or dirt) and sprockets seem to last and last--I've gotten almost 20k miles on a chain, 30k on a rear sprocket, 20k on a front without making much of an effort.
Hope that helps.
(just arriving home after 38,000 miles on the KLR)