More urgent than for other sites.
WHY IT MATTERS MORE
A shop's database changes constantly: orders, customers, stock.
A backup from last week is missing every order since.
WHAT TO BACK UP
Files and database, together.
The database is where orders live.
HOW OFTEN
Daily, at minimum, for an active shop.
More frequently if order volume is high.
WHERE
Off the server. A backup on the same account is lost with it.
BEFORE ANY CHANGE
Updates, plugin installation, theme changes.
Always.
THE RESTORE PROBLEM
Restoring a database loses every order placed since the backup.
For a shop, that is a real cost.
Restore files first where possible, and only the database if genuinely necessary.
WHAT TO TEST
That you can restore. Occasionally, actually do it on a staging copy.
WHAT TO CHECK MONTHLY
That backups are running and recent.