Raspberry Pi isn't designed to work 24/7 either
Most consumer hardware isn't specifically
designed for 24/7 operation (opposed to server hardware), but in most cases it's totally fine to keep it on for years in a row. In my experience, all you have to do is regularly clean the cooling system from dust. Hardware without a fan is even easier.
They are, don't worry..
Exactly!
Yeah, just make sure it's not too hot/humid and then most computer should able to run 24/7 with little or no problem.
I've never considered humidity, but that might come with the climate here. As long as the hardware is slightly warmer than it's surroundings, I don't expect condensation. I've seen problems with using cold laptops (coming from outside) in a warm room though, but ironically that's from turning it off, not from keeping it on
OP has long abandoned this topic, and I
don't believe he cares. So OP goes on ignore so I don't fall for this again.