There are grinding gaps at level 70, level 130 and level 160.
It is the moment that you are running out of quest and have to start grinding to reach next level and have quests available again.
Honestly, they are the most boring parts in the game for me.
I lost two of my friends at those levels becuase they do not like grinding while I also think that excessive grinding is not fun at all.
Many people will agree that the first 50 level is the most fun moment in this game. That is why lower than 10 % of players(characters) can make it past level 70.

