Various XP questions :

[Frizze]

Get one class to 70 first then there is bonus XP for the other jobs, IIRC.

Any class that isnt your current highest level gets bonus exp. This is the "armory" bonus. When your first class is level 10, if you pick something new up it starts getting the bonus exp immediately(as in, you dont have to wait until some set level before your lower level class gets the bonus). The bonus starts at 100%, then either at level 50 or level 60 it goes down to 50%. If your new class passes your old one and becomes highest it stops getting this bonus, but now your original will get this bonus until you pass it back.