Most modern amplifiers, both tube and ss, employ some kind of inrush current protection, even something as simple as a cheap thermistor -- (this is not to be confused with surge protection.) When you consider that both tube and ss amps take about the same amount of time to warm up and stabilize, as Paladin says, there's really no reason to leave even ss amos running all the time. If you'll be home all day, flip 'em on as soon as you get out of bed; otherwise as soon as you get in from work. It's a matter of having a routine.
Fine solid state preamps and DACs are another matter. They have very sophisticated and sensitive power supplies, and I think it's the PS (and not the audio circuits) that need to stabilize; and for reasons I don't understand, they can supposedly take a bit longer. My Levinson preamps and Wadia DAC don't even have power switches, and besides, my whole front end only draws 50W at idle (without the tube tuner on ;-) All the same, I now turn them all off at night (save the planet!) and on again first thing in the morning. I don't require ultimate fidelity for NPR News in the morning, and by the time I'm ready for good sonics, so are they.