Mahdrek's Noob question thread

Hi all. i just started this game the other week and am about to start tier 3 classes and had some questions.
1) DERP's : are they based on your progress in the game or are they the same for everyone ? if they r the same for everyone i avoid them till when ?
only downside of them is stats ?
sorry actually dont know anything about them as ive avoided them so far
2) is there any huge mistake that a new player can make that will gimp his progress ?
I'm thinking the game is open ended, meaning i can choose which dungeons or quests to do in any order as long as not too hard. i can choose what classes etc to unlock as there is no huge benefit to one before the other timing wise?
any tips in proper progression if im wrong in my above thoughts would be very welcomed
thank you
1) DERP's : are they based on your progress in the game or are they the same for everyone ? if they r the same for everyone i avoid them till when ?
only downside of them is stats ?
sorry actually dont know anything about them as ive avoided them so far
2) is there any huge mistake that a new player can make that will gimp his progress ?
I'm thinking the game is open ended, meaning i can choose which dungeons or quests to do in any order as long as not too hard. i can choose what classes etc to unlock as there is no huge benefit to one before the other timing wise?
any tips in proper progression if im wrong in my above thoughts would be very welcomed

thank you