Joined: Jan 2010
Posts: 9,835
Likes: 1,816
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
Modern drivetrains specify 0.5% wear for chain replacement.
Previous recommendations were for 1%, with replacement of all chain and sprockets.
Something like hill repeats is very stressfull, to the point that a timely replacement of chains is advised.
I can't believe you wear them out that fast. Which brand and model of chain?