All of my services run on LXC containers. Some files and configs are backed up to NAS and offsite. The containers are snapshotted in their entirety before I do any work on them. A snapshot takes 5 seconds to make and causes no downtime. If I regret a change or mess it up, I can restore the snapshot in under a minute at the cost of some seconds of downtime.

My only non-container machines are my desktop (doesn’t count), my NAS and the Hypervisor. The Hypervisor is very clean and wouldn’t be much fuss to reinstall and the NAS is literally just Debian with NFS. All of these have a regular rsync which runs to backup the important files.