4-6 years as a warfighter CRO is about right before moving on to more admin/supervision duties.
We have quite a few PJs that become CROs each year. Obviously they are pretty good candidates to pick from already, but they must go through the phase 1 and 2 assessment just like every other cro candidate. If you are looking to hit the med, but want to take advantage of the pay and responsibilities o heavilyf CRO, doing a PJ to CRO transition may be the best option for you. Typically if a PJ goes CRO, we will work to keep their paramedic certification up to date, although there is no guarantees and the CRO will rarely use those skills as Yukon eluded to.