Take a look at Jays Audio Lab on FB! He's gone through over 60 amps in his search for perfection! IMO this is certifiable behavior - time to call the men in white coats!
Agree. Has his room changed in that time? Have speakers, DACs, other things changed? Has his preferences changed during his auditions? What keeps his compass pointed at the north star and his variables stable? Or is this more of a kind of performance -- something like one would see at a carnival. "Watch the spinning plates, kids."