Thats also roughly when you unlock retainers, which allow you to sell things on the market board(and buy things? or was that always open? its been SO long).

One thing i always liked is the way the systems synced up. A level 30 gatherer will get materials that a level 30 crafter can use to make gear that a level 30 fighter might want. There are lots of ways to get gear so it isnt strictly needed, but its a nice boost from time to time. And having crafters leveled makes gearing up a 2nd(3rd, 4th, etc) class much easier.