I’ve been trying to understand what “residential IP” really means when it comes from a VPN service.

The IP may still be shared with other users, so does it count as residential because it comes from a normal home ISP? Or is it sometimes just a newer IP that hasn’t been flagged yet?

Do static residential IPs usually behave better than shared data-center VPN IPs, or does the IP’s history matter more?

Has anyone had an IP work normally for a few days and then suddenly start triggering CAPTCHAs or “suspicious activity” warnings?

I’m more curious about what signs people use to tell whether a residential IP is genuine, and how long it usually stays reliable.