How hot is too hot?

I run a Creek Classic 5350 SE integrated that gets up to around 105 degrees or so in the cabinet. It's not an ideal cabinet, for sure, but I'm dealing with it as a constraint. Does anyone know how hot is too hot? I know that servers and computer equipment really should not be run that hot if you expect them to last. What about audio amps?

105 degrees is not very hot at all.
You are 98.6 and even over 100 if you have the flu.

Or do you mean 105 celsius which could boil water.?

Class A amplifiers can fry eggs without the proper heat sinks.
Can you/your handyman install a portable fan? Because many amplifiers have fans, I noticed, unless you don't care about longevity.

Here is my rating system

normal is to be able to keep your hand on the heatsink as long as you want to.

Warm is when you can only leave your hand on the heatsink for a few seconds before it becomes uncomfortable.

Too hot is when you cannot leave your hand on the heatsink for more than a second.
55 deg C or 30 above ambient is the rule of thumb for Class A. 100 deg F is nothing to worry about.