There can be no hard and fast rule for getting recurrent check rides.
A lot depends on the background, ability and the mindset of the person involved.
We are in the warbird rebuilding and flying business, quite often after getting a machine airworthy we must test fly it, generally there is no one avaliable who is current on type.
So what should we do, leave it sit and just admire it?
Then there is recurrent training for our clients, they park the airplane in the fall and come spring we are called to do the required recurrency check rides....now we once again have the chicken and the egg problem.
I see one poster here requires a re check every 31 days, so what are we supposed to do with this airplane that no one has flown for six months?
Chuck E.