Thank for all your comments. I am pretty good about the chains. I have only used XO1 chains for a few years now as they have great durability (assuming you look after them). I change them on the same schedule
@ozzybmx uses.
A bit slack on cassettes, though. (as you can see).
So into the bin for the pictured cassette, different wheel for this mornings short burst and back on the hunt for a new cassette. The XT/XTR 12 speeds have been a bit hard to find. I have been looking at the Garbaruk cassettes, so maybe I will give that a whirl. Thanks!