In TBC I never had any problems getting dusts or essences, I still have my bank alt with a few stacks of Arcane Dust and Cosmic Essences.
However in WotLK I am burning right through all my Infinite Dust from just leveling tailoring alone. I have loads off Dream Shards in my bank for when I get high enough to grab the other recipes but I just can't seem to keep up, I'm not getting any greens at all from doing my Sons of Hodir and Oracle ones and the only place I haven't got the Achievement for is Icecrown.
So how do you keep up your stockpile? It was never an issue in TBC, I got enough greens on the Isle alone to keep more than I needed (hence all on my bank alt) but now I'm stumped. Buying greens on the AH is the only thing I can think of but most of the greens go kinda steep and it seems like it'd be more useful just to buy it directly.
Tailoring is kind of the same, I remember after I made my FSW boots I just needed to farm a few spidersilks and after making a few blues I was there. Now I just have a bunch of crappy epics that are useless to me.