"Doesn't current surge, the first 1/2 cycle to saturate a transformer count as stress?"
Yes it does create rush current - but there is no evidence that it shortens life of electrolytic caps. It does nothing to transformer or rectifier.
You won't fint MTBF on any datasheet of any transitor, diode, IC (digital or analog) etc. - probably because it is in order od few hundred years. The question was if switching on/off is shortening life compare to keeping it constantly on - it doesn't. It will shorten life of switches, relays, tubes but not the SS stuff.
Yes it does create rush current - but there is no evidence that it shortens life of electrolytic caps. It does nothing to transformer or rectifier.
You won't fint MTBF on any datasheet of any transitor, diode, IC (digital or analog) etc. - probably because it is in order od few hundred years. The question was if switching on/off is shortening life compare to keeping it constantly on - it doesn't. It will shorten life of switches, relays, tubes but not the SS stuff.