Relax, its just the normal lack of reading comprehension. People can't read, don't get that AC Infinity is a name, they think its air conditioning, then one after another misconstrues until its one big mess. Welcome to A'gon, short for the agony of audio.
Coolers are really only useful if the thing is getting hot to the touch, and even then only when its long and often. Otherwise you can bet your unit has thermal shutdown and will be fine. 77 degrees is practically refrigerated and beyond overkill.
Next question, longevity. Heat itself, as long as its not excessive thermal shutdown level heat, is not the problem. The bigger problem is thermal expansion/compression cycles. This together with good old fashioned oxidation is where most wear comes from. So if you want it to last a long time the answer is simply leave it on.
Finally there is sound quality. Being a receiver there isn't much, but what there is will certainly be helped by leaving it on all the time. What will happen is the sound quality will improve very slowly and gradually over time and you won't notice any difference. But you will get used to it. Then one day you turn everything off, and when you turn it back on guess what? You will notice its a lot worse! So there was a difference after all, it was just hard to notice because it was so slow and gradual.
Power cords and conditioners are similar, by the way. The noise they remove was never there in the sense of anything obvious you could hear and point to, like static or hum. Instead the noise is so woven into the fabric of the music it doesn't seem like noise at all- until its gone. Just like leaving things on 24/7 didn't seem to improve anything- until it was gone.
We now return you to our regularly scheduled program.
