Originally Posted by realityinabox

I put ~1500 miles on my first chain before learning about chain "stretch"/wear. I ordered a Parktool chain checker and the chain was very worn. I replaced the chain one evening and threw out the old one. When I left for work the next morning, my rear derailleur was binding pretty badly. I was able to find a gear that worked, so I continued riding on that single gear for the next week before I could change out the rear cassette.

I've put roughly 450 miles on the new chain, perhaps 80 of which were on the worn out cassette (I'm not 100% sure on my miles, trying to estimate based on Amazon order dates and Garmin history). Yesterday when I was cleaning my chain, ran the chain checker on a whim and was shocked to find that I was already dropping in on the 0.5 measurement. The 0.7 measure is still good, but I am still shocked that this chain has worn out so quickly.

How long do chains typically last? Could that week of riding it in the single gear on the worn out derailleur have worn it out that much? I suppose if the front cranks and/or the rear derailleur sprockets got worn out from the old chain they could be wearing the chain out at a faster rate.