I think every club has some sort of rule like that. At mine it's 28 days, I think irrespective of total time but it doesn't have to be a certain length as pilots obviously vary a lot in ability. For some people the ride might result in a fairly long check and perhaps a need for more work on something, maybe landings. For others it might just be a circuit or 2 then you'd be off.
I suppose it's a fair rule because they don't want to get their planes wrecked and it probably helps keep insurance down. Also it shouldn't be required too often because in the summer it isn't too hard to fly every 28 days.