How to prevent server crashes?

I noticed that on rare occasion the server will crash (app stops working).

How can I prevent the crashing from taking place? I have a feeling it's regarding prop spawning.

Anyways, what are some good addons, techniques to help further administrate and protect your server while you may be sleeping or AFK.

Lots of people would probably like an answer to this so on behalf of me and everyone else, help us!