They move up from "baby units" to bigger ones, after a couple of years, if they avoid too much bad press. Then they retire, or are "administratively separated ". Or, they mess up but LD still likes them, so they demote back to a baby unit.
Jones was at Darrington for YEARS, only leaving after that Sgt killed the shackled inmate.
Rotation? If it's in the policy, they ignore it as they see fit.