How many watts do you really need?

@polkalover 

"its all about headroom."

A good 5 watts per channel amplifier, efficient speakers in an average sized room, all the headroom you'll ever need.

Even if an amp is ONLY in Class A up to 40 wpc, that is so much power for ANY speaker that it will be playing at such a high volume level there is no way anyone can hear the subtle difference between Class A and Class AB operation; your own ears will be employing muscles to restrict motion of moving parts to protect the ears.

I personally favor amps that prioritize operation at less than one watt.  My 5 wpc amp has plenty of reserve for my purposes.

It’s easy to get hung up on watts when perhaps the conversation should be more focused on current capacity vs. time. This is where two "100W" amplifiers can differ significantly, and this differences translates directly into performance disparities that are plainly audible. One might take note of the relatively large, high current power supplies used in more expensive amplifiers. 

@faustuss  VERY SUBJECTIVE, 5 watts is all YOU! will ever need. Also make sure you know what HEADROOM means in AUDIOPHILE Speech or when describing how much headroom someone actually needs in their system. Remember not everyone like or use efficient speakers in their system.

And again, not everyone uses speckers like KLIPSCH, and most care not to. Surely not when it comes to ultra-high end system setups. But you will find them in a basic or average layman’s Audiophile system. Not everyone listens to or even care to have a tube amplifier setup that only actually needs 2 to 3 watts, but you suggest 5 watts, and with that you are not looking for headroom in amplifier wattage. Once Again, it is all very ((( SUBJECTIVE ))).  Some of us just listen with headphones > To each his own.

Good day and Peace to All

@blackbird55 I didn’t suggest 5 watts faustuss did.  But I get what he’s saying as well as you.  My amp is 330 wpc hybrid tube amp. Happy listening