When I inherited my bike, it had Shimano Ultegra 6700 53-39 front rings and a 28-11 (10 speed) on the back.
When I got my Kickr Core, it came with a 25-11 (10 speed) cassette. And I’m still using the same chain (maybe I shouldn’t, but I don’t know better).
I’ve been considering for a long time to update my rear cassette to a 30 tooth set. Tho it looks like that would be a 30-12 10-speed (unless a 30-11 exists, but I can see why that may now work due to the ratios) to put on my Kickr Core, but then to also to be able to move to my rear wheel when I get back to outdoor riding.
I likely need a new chain sometime soon since this one is at least 4 years old. I have a brand new chain that my dad gave me with the bike 4 years ago that’s the same size as the one that was on the bike when he gave it to me with the 28-11. If I upsize my rear cassette to a 30-12 will my current size chain still work? Or will I need the next size chain?