First and formost is clearly stating it when group is formed - it won't take that long......
I like to when grouped with people i don't know is need roll on everything and tell them to as well... everyone needs credits, and there is an AH. you can always ask for an item and or swap with group members.
if it is my friends its need only if you are going to use it, mains first. meaning you may be playing an alt but we know your main. if they need something that your alt can not use I trust you as my friend to need roll on it properly, everything else is greed roll. However with my guild and friends I will almost always give them things before placing on the AH so that shows my thoughts on the need greed thing.
