I wonder how many hours would pass before you caught this and set up a new server? What if you're on vacation?

Honestly there's a little bit of "because I did it myself and I'm awesome it won't fail." That's hubris and very typical of young engineers.

Letting someone else manage it for you is probably the right thing for a startup to do. You just need to choose someone with a good, proven uptime record. That is what should guide your decision.. with so many things in engineering.