The leveling speed dramatically decreases. You'd better not just focusing on leveling while ignoring PT grinding. It's more difficult to grind your PT when your level is quite high. So, it's time to test your patience.
For level 21-25, you'd better level near outpost according to quest information, killing such monsters as Snatcher Hurl,Lava and Gaff. After level 25, you have to search the four corners of the map to kill those higher levelmonsters. The monsters there spawn fast and there are enhanced monsters, so you'd better party with cheap RF Online gold other players to take care of each other. Players will loot monsters in the same area more since their leveling speed tends to be slower. If you are bold enough, you can go to arms factory 213 HQ and kill monsters there. The monsters there are high level, so you'll need more potions. Leveling alone is not a good idea. Better party with other players.
Personally speaking, although specialist is capable of fighting, but it is a crafting-oriented rather than a fighting-oriented class. And it's seems that the success rate of item upgrading of specialist is a little higher than other classes.