The way Charlie Day told it to The Wrap, it sounds like the only thing that could keep a record-breaking Season 15 from happening is FX. As busy as he and the other members of the It's Always Sunny In Philadelphia cast are at the present, Day appears to indicate that all of them are down for getting together to break that record should the network want them around longer. One would imagine FX won't be making any decisions regarding the series until it sees how Season 13 goes, and even then they might wait until Season 14 to make an official decision.