A short story of a bicycle chain…
I got my Ridley carbon fibre bike when I retired and have not used it a lot. I told, I think, in an earlier posting about how it had a 10speed chain with a 9-speed link, fitted by the factory which caused a lot of trouble until I diagnosed it and got a new chain fitted.
The other day while cycling, and with about 2000-3000 miles on this chain I felt a skip-skip. Had a look.
One of the links had become twisted (having becomed jammed during a rare dechaining episode) so I managed to get home and measuring it with my Rohloff chainwear tool (well-worth having. Much easier to use than messing with a ruler) found that it merited replacement. I had a spare chain and when I fitted it, I couldn't handle the old chain as it was so filthy so I guessed how many links I had to take off and fitted it. This was done just before a cycle with my friends. I had grossly underestimated how many links to remove (I had a compact system) and had removed four. During my spin I found that the chain was too long by far and skipped on the smaller chainwheel on some of the bigger back sprockets. Mick guessed that I'd need a new cassette but I was able to manage with the big ring.
When I got home, I found that I had to remove 8 further links to get the right length.
When I tried this it was perfect and didn't skip at all, nor did it on a 40-miler today.
So, try it before you change the cassette. Cassettes are not free!