Quote Originally Posted by Nutz View Post
The guild quests are no longer advertised on the map, though the NPC (guild receptionist) still has a quest icon above their head. As Raldo said, the requirement is completing your level 10 class quest. After that your guildmaster will tell you specifically that you're free to check out other guilds and then some help text will pop up and give you a run down.
This is exactly it.

Of course, only so many disciplines are in your hometown - you'll need to complete the level 15 Story Quests to get your airship pass, at which point you'll be able to fly to other cities and get the various disciplines unavailable to you.

For a final note, you have infinite freedom to level classes at whatever pace you want; and can level every class to max in time if you want. You also get +50% base EXP gain on classes that aren't your currently highest levelled.