Since I managed to wreck the rear shifter on the Streetmachine[1], and the difference in cost of a replacement was neutral I figured this was as good a time as any to go 10-speed. I've currently got a mixture of 9 and 10 speed in the fleet, so the existing chain and cassette can be used up elsewhere in in due course.
So, new shifters, three chains and a cassette. And a couple of spare 10sp quicklinks for the toolkit. And a new mirror and brake levers[2] to replace the ones that were damaged. And some gear cable outer that I needed anyway.
Bah.
[1] Microshift 9-speed bar end. This has lasted many years longer than the Dura-Ace ones that came before it, because the indexing ring isn't made of cheese.
[2] 4-finger levers with rubber grippy bits seem to have gone out of fashion.