Originally Posted by
kmac27
How do you know when your cogs are worn and how do you know whether to replace a cog or replace the whole cassette?
The telltale signs of cassette wear are 1) your chain slipping and skipping while solidly in gear 2) when you put a new chain on and your chain starts creaking and grinding because it can't quite fit onto your worn cogs and 3) the valleys in between the teeth of the cog start looking a little more like a crashing wave shape than a symmetrical wave.
I take pretty good care of my chain so I usually swap out a new cassette with a new chain but to each their own.