I've been getting a bit of skipping and it sounds like its coming from the back. I haven't changed anything yet and I am wondering of it's the sram 970 cassette or the XT freehub thats causing the problem. Have a look at gears 4&5 in the photo and see if you think the cassette is past its sell by date.

not sure about gears 4 & 5 I can't even see a photo?

Oops I can see it now. I agree with C-A below

😆

You can't tell by looking. If the chain and cassette have been together then there shouldn't be any skipping unless it's super worn.

The chain and cassette have been together and the chain doesn't look very stretched.

Looks pretty worn to me. A lot of the troughs between the teeth are uneven, being worn more on the 'drive' side of the teeth.

Makes them look like shark's fins, look two teeth to the left of the 32T stamp on the largest sprocket, almost at the bottom of the picture.

New cassette and chain recommended. You should be able to feel any lateral play in the freehub.

I don't think you can tell by sight if a chains stretched…If they've been togeher for ages and its slipping I'd replace the lot

Some of those teeth look a lot more pointy than they should be to me, I'd say it was worn but it is hard to tell by looking.

Thanks for the advice. Sounds like a new chain and cassette then.

And the photo has gone now

cassette photo