Staging is not one copy. It is two copies that behave differently — the files and the database — plus a rule about what is allowed to travel back to production. Most staging accidents I have seen were not broken code. They were a database import that carried production's user table into staging, or staging's wp_options table into production.

This is the setup I use: clone files, clone the database, rewrite the URLs, make staging unable to hurt anyone, then sync back with a narrow allowlist.

Step 0 — write the boundary down before you copy anything

One rule covers almost every case:

Content a human wrote and code a human reviewed may travel.…