I’ve been running Valves for nearly four years. Only two Signal Valves have been swapped out. One went microphonic; the other had the silver getter material flaking from the top.
Otherwise, extremely reliable so far. Will be serviced next year though !
Now looks like this. Work in progress; soon the Bluebells will flower, then the Summer Meadow flowers, followed (hopefully) by Forget-me-nots which I installed in seed form back in February…