How long does it take to get a job class to 50?

[Zidclo]

Grow up to 50 it takes me about a month.

1-30 leves
30-45 partys (or leves if you can't find party, but is slower)
45-50 spiritbound party mostly

Time for another noob question from me! What is a spiritbound party?? Apologies if this is something simple and I'm just overlooking easily accessible information.