From about level 800 odd, there are quests that require bucket loads of components and at least one expensive purchase-only part. There are also quests that require you to carry one item for about 15 odd levels before you can use it. There is Riangi. You carry a recipe from level 911, and gather components till level 918. That's just four quests on the way. But Karthak? That's a whole other torture in itself. You are to endure the endless walking and multiple quests (that actually begin from the Xanlin area) and continue on it for 30 odd levels.
An example: A Favor for a Friend. This level 959 quest requires inventing one item, for which you need three parts. Each part requires those several components and that one purchase-only part. So just inventing this main quest items costs you about 20 mil plus of gold. Then you also get to invent yet another item, just because.
(And best part? You receive a quest item as reward that you would need at level 970)
Definitely no fun.
After subjecting my guild with all the ranting, I thought I'll share my misery with other peeps as well
Now go back to your work!