Yes, I have made the mistake of replacing just the chain on a worn out cassette, and having to have the whole lot done again. This time I was just a tad surprised that the cassette had worn out so quickly. I should have taken them up on the offer to phone - if the cassette wasn't that bad I might have lasted it out over the winter goup season and replaced it in the spring. Oh well, at least it is all as good as new now!!