This was a pretty hefty patch. I play a decent amount and all I've done so far is the extremes, ultima, king Moogle once, and ct like twice. Haven't touched the hardmodes, or even checked out housing of Pvp yet, let alone started repeating/grinding shit to any significant degree(minus Garuda, fuck that mount won't drop).
Not three months of content by any means, but I'd say a solid month or two for most before boredom sets in, and then according to their timeline it's just another couple months till the next update.