What I have personally found is that there are a couple reasons it happens. Normally I think that the original wick gets some black charred gunk on the end of it, and/or it has burnt away from the coil.
There are a bunch of "fixes" for it. I think by doing the above, you are basically dripping on to the atty. Which is one fix. another is to take the needle plate out and try to clean the wick of the black sludge off the end. Another is to slightly push down the wick to try and get it in contact with the coil better, but too much and you can make the tanks leak.
What I have found works the best, is to replace the wick with a new one. Very simple to do, I can do it in about 5 minutes if I take my time. Only drawback I have seen to this method is the silica rope used for the wick doesn't seem to last quite as long as the original. hopefully we can find a longer lasting type. This should fix both the dry hits and the leaking issue. I have one atty that was pretty much shot, leaked like crazy, dry burns, you name it. I have put a new wick in it and am going on about a week now with it working perfectly. Not bad for 5 minutes and about $.25 in wick material. IMHO, the time and money it takes to replace the wick is worth it for the convenience of the ego-t in general.
I do a few dry burns when I have it apart and can see the coil, and that really seems to help too.
here is the best thread on how to replace them.
http://www.e-cigarette-forum.com/forum/ego-type-models/169520-simplecjs-ego-t-wick-mod.html
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