FFIII class changes

Exactly when am I supposed to get new classes other then Onionknight, Fighter, Monk, Black Mage, Red Mage, and White mage??

Get to the next Crystal. Just like in FFV.

Later. :p

Okay, more specifically, (SPOILER)after beating Salamander in the Flame Cave.

Trust me, you'll have classes coming out of your ears before too long, and you'll probably not use them all.

I must advise you not to use Scholars. It's tempting to see what the new job is like, but you'll soon wind up wishing you'd never been curious. You'll get the new classes soon enough ;)

"Ok, I'll level with you. The Scholar sucks. Like... a lot. He's good for ONE fight, and that's it. He can use the special skills 'Peep' and 'Scan.' Peep checks HP and MP of the monster, while Scan checks weaknesses. They're essential for this one MagiMaster-type fight, but after that it's all over, baby. You can hang em up with your Underwater Materia and most of Zidane's 'Skills.'"

You copied from the website