Glossary
A redirect sends a request for one URL to another. A 301 declares the move permanent and passes most ranking signals; a 302 declares it temporary and is intended to leave the original in place.
Using a 302 for a permanent move can leave the old URL indexed and the new one weak; using a 301 for a genuinely temporary change makes the change hard to reverse cleanly. The status is a statement of intent and search engines act on it.
Chains where one URL redirects to a second and then a third lose signal and slow crawling; loops make pages unreachable; and mass redirects to the homepage tell an engine the old pages have no equivalent, which discards their value entirely.
At least a year, and longer where external links point at the old URLs. Removing them early discards the value of every link and bookmark that still uses the previous address.
You can, and it is usually a mistake. Search engines treat a redirect to an unrelated page as a soft signal that the content is gone, so the value of the old page is discarded rather than transferred.
A redirect sends a request for one URL to another. A 301 declares the move permanent and passes most ranking signals; a 302 declares it temporary and is intended to leave the original in place.
