personally id go in the incriments they add on 1k to 8k is alot if you ask me and might make you seem desperate if you shoot for it before they ask.. not too sure just putting my ideas out to you.. =D
3x seems to the lucky number.
My walmart discover card is due for increase very soon currently stands at 1k. I wana hit the luv button for 8k. I use heavy and PIF always. Is that too high to ask?
Probably, but depends on your total credit picture. IF you've got the credentials to support a 8X increase, then gopherit! They will most likely counter, as the others have stated. Discover is fairly conservative, so don't be disappointed if you don't get that. 3X would be considered a fair increase.