Moderator, Iberia Airlines, Airport Lounges, and Ambassador, British Airways Executive Club
Join Date: Feb 2010
Programs: BA Lifetime Gold; Flying Blue Life Platinum; LH Sen.; Hilton Diamond; Kemal Kebabs Prized Customer
Posts: 63,850
I thought it was 28 days, but that's apparently for Elemis. So you can book further ahead than that (certainly months), and there's no time limit for usage. Unless on a double longhaul flight connection and looking to get some shuteye then I'm not sure I'd bother.