So this morning's commute was fun - as I start pedaling after an intersection, the chain breaks. Yay! Chain breakage is one of those things I'd like to avoid as I enjoy my teeth where they are. Thankfully this time it broke as soon as I put my foot down, so no harm done.
I'd been checking for stretch quite often, but the thing was (and is still) under 1/16" of stretch over 12 links. But still it failed. The failure was at the connector pin on a 7-speed Shimano Hyperglide chain. The lip on the pin wore down and the plate pulled away. The chain had never been broken since installation.
Is there anything one can check for other than stretch? For what it's worth, the chain in question was original on a bike I've owned for 16 years, but has only seen about 3000 miles. So certainly it was rather old. But my impression was that years don't matter if the chain checks out OK. I've had a replacement chain at home waiting, but it seemed wasteful to toss a functioning chain.
So is there a sane limit beyond which one should toss a chain for sanity's sake, even if the tape measure says it's OK? Looking back on it, I was an idiot not to just throw on a new chain, but I was raised not to waste anything. In any event, I'm still intrigued why it didn't show virtually any wear.