Let laptop down overnight?

I'm downloading a game on Steam, which is about 80GB. Since the whole will probably take at least 8 hours, I just wanted to let the laptop work overnight. Can I do this without hesitation?

Can you do that while you're near and make sure enough fresh Ran comes?

If the noise of the laptop fan does not bother you, you can of course do that.

My old T61 Thinkpad was set up by me 4 years ago as mail and file server.

It runs since then without interruption.