Invent

If you want to max your [item=219150] yield, keep at least one invention unlearned! (so anything marked 'Invention' in the Engineering window). This includes prototypes and those learned from [item=219192]. For details, see the spoiler tag.

Spoiler

Once you learn all inventions, they no longer drop from Scour Through Scrap. This sort of makes sense, but Disassemble Invention also gives about 15 [item=219150] on average so you lose out on a lot of scrap (which in turn give parts to use or sell). Disassemble Invention takes exactly two minutes a stack at Crafting Speed 75%, so in the long run this is definitely worth it. Scour Through Scrap will give some leftover scrap (and notes in case you still miss patterns from [item=219192]) instead of inventions but this pales in comparison to the thousands you get from disassembling.

I can now first hand confirm this: wanting to max out my knowledge from First Crafts the only pattern I'm now missing is [spell=447370]: Invent and Scour Through Scrap give me [item=221961] consistently. If you go down to just one invention just bank it to prevent learning it by accident. Every other invention will now be [item=227890] that you can Disassemble Invention at will.

I'm not sure if this effective nerf is intended but it seems to be, considering the 'leftover' from scouring after you learn all inventions.

Thankfully they have just changed the cooldown on this - WAS one day (24 hrs) but now is 20 hours - so you can do somewhat earlier the next day for added convenience - they have learned from Everquest where people complained that daily things sort of get later every day otherwise.

There are 14 "Prototype: " items you get from Scour that teach you recipes - don't use the last one! Just 'Disassemble Invention' your last one any time it comes up when you Scour. I've listed the 14 on the Comprehensibly Organized Ideas page - use this link to get there and be sure to upvote selerik's awesome post. (My post with the 14 items is right after his.)