Originally Posted by
Al1943
Chains should be replaced when any one foot interval has "stretched" to 12 1/16 inches. By the time it reaches 12 1/8 inches it's probably too late.
Yep - That's right. 12 1/16 = time to replace chain. 12 1/8 = rplace chain plus cassette plus possibly a chainring or two. First option is more economical.