I am one of those who still prefers/uses pre-filled cartos, though I am planning on buying some ejuice and try my hand at re-filling a few. I have noticed, or so it seems, that sometimes after a cartomizer seems fairly exhausted (some vapor, but no more flavor), if I put it aside for awhile, when I try it again, the flavor seems to "rebound" and it is pleasurable for awhile more. Just curious if this is just my imagination, or have others noticed the same thing?