When you leveling,I don’t suggest to filter other greens an leave only double rare-extremely small chance to roll them and you missed valuable items,that may help you.This filter is designed to help you late game,when you swim in loot (especially Crucible) and l only top rolled MI is worth using.
^^^^^^^What Nery said. Do NOT sell greens. If you see that a vendor is willing to pay more for a green item than your purples, it’s probably really good.
Personally I would not suggest it, unless you are really swimming in loot.
A combination of a good rare prefix and a good magic prefix like vitality, protection, readiness, attack and celerity/alacrity can be more useful then a number of double rares.