The single most valuable thing you can do for a website.
WHAT BACKUPS PROTECT AGAINST
A compromise A failed update An accidental deletion A developer's mistake Database corruption Hardware failure Losing access to your hosting account Your own error, which is the most common of all
THE PRINCIPLE
Almost every website disaster is recoverable with a good backup and unrecoverable without one.
A compromised site with a clean backup is an afternoon's work. The same site without one is a rebuild.
WHAT PEOPLE ASSUME
That their host has a copy of everything, indefinitely. Hosting backups have finite retention and are a safety net for infrastructure events, not an archive.
That a backup exists because a plugin was installed. A plugin configured and never actually running is extremely common.
THE UNCOMFORTABLE TEST
If your hosting account disappeared entirely this afternoon, what would you still have?
If the answer is nothing, that is the problem to fix before anything else.
WHERE TO START
One full backup, downloaded to your own computer, today. Everything else builds from there.