Learn more about outfit armoury resources from the PlanetSide 2 Wiki
Target stock levels as once told by Rewe
These allow us to convert the different armoury currencies into more valuable ones.
Green - Auraxium
Blue - Synthium
Purple - Polystellarite
Purple is the hardest to earn so should be prioritised.
In general, it is advised to keep the blue from being full. If green turns out to be full we can get rid of that more easily than blue (with modules and anvils).
Crafting priority should be that we have as many orbital strikes as we can. If we have enough resources to craft but already have 2 OS we should make sure that we have the required Colossi and Cit Shield.
If all those criteria's are met (meaning that we have 2 OS and can craft another) one may use an OS casually
The reason of the focus on orbital strikes is the impact they can have in the game
Oh, and as Henry said: we don't need to redeem expeditions. If we are full on blue and you redeem a blue expedition a random orphanage may burst into flames