Leaving my amplifier on ok?

MANUFACTURERS Recommendations are the only ones worth seriously considering

Good point.

I have had some manufactures advise to "leave on" ss components, and to "turn off", when not using for a while.

Most modern designs are going to have a standby mode where the component consumes very little power. Usually .5 watts or less.  It’s pretty apparent that they are intended to be in standby mode when not in use.  I noticed even holdouts like Naim have finally embraced energy conservation and have this feature in the new classic line and statement amps.  
Older designs without a standby mode I can’t really say.  I have owned amps that consume 20 watts or more at idle. That can add up over time so personally I turn my stuff off. But I’ve never owned a mega expensive amp, so my experience may not be applicable.  In this industry there are many specious ideas that are spread around, shared and reinforced. Stay skeptical. If you’ve got a really expensive amp, and want it to last decades, try calling a service center to get opinion. 

most new components have soft start circuitry that dramatically reduce the inrush and damage to components. So this shouldn’t be an issue with newer components.

@minorl Even if that’s so, which you’d need to confirm with the manufacturer, the point you’re missing is that the constant temperature fluctuations between cold and warm/hot also degrade electronic components faster — this according to Steve McCormack.  I’d refer you to my prior post for more context if you haven’t read it already.

My 'go to' Audio EE, who has designed and built a selection of my systems devices, and carried out circuit corrective works on another owned device.

Made it known to me in the very earliest days of out relationship, to always have eyes on the devices in use, to Power Off after use and revisit shortly after Power Off for peace of mind.

This is a discipline maintained to date, which was first strongly suggested over 25 Years ago.

This advice even though extremely valuable, is seemingly the anti-thesis of the description being given of how another EE is endorsing certain paractices.

On the matter of early component failure being realised through heat fluctuations is surely a case of stepping over $'s to pick up Cents.

I lost my home due to an electrical fire occurring, as a result of being foolish and try to prolong the life of a devices components that might only cost a few cents to replace once spent.

All Cap's, Resistors, Switches are going one way, and that is spent as a usage life. Ask a EE.  

@soix, Thanks for the information.  I don't believe that it is a constant temp flux, because one isn't turning on an off like a 3 year old.  It is turned on and let warm up.  Hence the word warm up.

however, I appreciate your input and will look at your other post/responses.

any good information can't hurt.

enjoy