Training Multiple Classes/Jobs

[rabbitzero]

Do you need to pick a job? Or is it ok not to and just play main story quests without it?

For soloing, which most of the story quests are, just being in the class is fine, and sometimes better because you will have cross class skills once you level those. Jobs are better for party play, but since all you have to do once you get the job is change the crystal and they level at the same as the main class for the job, it's easy. The job quests aren't too hard, and don't take long, so if you qualify, i'd say just do them. It can't hurt, even if you really never decide to use the job.