Have run a couple of SET monoblocks (Cary - am pretty much back to SS after 10+ years with tubes) and never found them to run any hotter than PP tube gear.
Coupling capacitors are really the only parts that 'age' in tube gear (other than the tubes). However, they generally last years (5+, as a minimum). Most of the tubeophiles I know consider coupling caps to be like tubes.............. one changes them out to 'hear' the difference between various coupling caps (V-Cap versus Clarity versus ???).
The very long thread (probably the longest on this forum - several thousand posts) on Dennis Had SET Amps (founder and former owner of Cary) in the Cary forum
https://www.audioaficionado.org/showthread.php?t=24170
has a ton of info on both tube & capacitor rolling.