People just figure things out for themselves. The Japanese mainly do it first; and as you know, they're really hardcore about this kind of stuff. Square also releases Ultimania guides for their games (~300-600 pages) which reveal absolutely everything, as well. Puts every published English guide to shame.

I just played through it using guides. I did the Mark Hunts and various side-quests (there aren't too many) as they became available. By the end of the game I only had a few more Hunts to finish off. Never really got around to doing that.

I'd never bother figuring things out on my own, though. I'd make mistakes and miss shit. Ultimately it would probably make me end up replaying the game.