Originally Posted by rpenmanparker

Usually there are no problems for a very long time as long as you just keep running both the chain and cassette. But your cassette is toast and won't work with a new chain. You will have to change that too.

Originally Posted by Drew Eckhardt

I don't waste time cleaning chains apart from wiping off the excess lubricant (now ProLink Gold, although I rode White Lightning for years until a squeaky link developed spontaneously on a long ride). I just add lube when they no longer run silently which can take about 800-1000 miles starting with the factory lube, but less than 200 on wet weeks.

I get 4500 miles / 7200 km out of Campagnolo chains (now C10) at which point I replace them due to degraded shifting from excessive side clearance although they haven't elongated by 1/32" over 11 inches.

I used to get 4 chains out of cassettes, although my current one is still running well at 22,000 miles (35,400 km).