Proxy rotation
Also called: rotating proxy, IP rotation
Proxy rotation is the automatic switching of exit IP address between requests or on a timer. It spreads traffic across many addresses so no single one accumulates volume, and it is the default behaviour of most residential and datacenter pools.
Rotation exists to solve a rate problem. If a thousand requests come from one address, that address gets throttled or blocked. Spread across a thousand addresses, each looks like ordinary traffic. Providers implement it either per request, or on a timer, or on a session identifier you control.
Where it helps and where it hurts
For anonymous, high-volume collection, rotation is the entire point. For logged-in work it is a liability: an account is supposed to have a stable home, and changing address mid-session produces exactly the pattern that stands out. This is the distinction most setups get wrong — they buy a rotating pool because it is what is advertised, then use it for accounts that need sticky sessions or a static address.