Pork needs a day to 'set up' - that is to become firm enough to be easy to butcher.
Beef benefits from being hung as a process called proteolysis tenderizes the carcasses - nowadays it is popular to hang to 21 or even 28 days.
Lamb - young lambs don't really benefit, but hoggets should be hung for a week. We only eat hogget here - best meat !
There is very little evidence of the same kind of proteolytic action taking place in hanging pig carcasses, and the general opinion is that you can butcher pork after 24 hours, and it doesn't benefit from being hung longer.
BUT it also does no harm to hang for up to 21 days, so if your butcher can't cut immediately don't worry.
Some people do think that pork should be aged, but taste and texture are very subjective !