How do you prevent your websites/server downtime?

Hi,
I've got a bunch of micro niche site, hosted on three different web hosting servers.

I am scared at the idea of losing ranking on search engines or getting penalized in case of persistent downtime affecting one or more of the servers.

How could prevent this issue? Do you know any service that can help me to keep my sites up in case of critical downtime?

I already use mon.itor.us to be informed of potential problems, but it's just a monitoring tool.

Don't buy the cheapest shared hostings. They're never good. As the saying goes, you get what you pay for. Investing a few more dollars on good hosting is a no-issue.

Of course, Amazon and Azure and other big cloud hosting providers most likely never go down.