Personally, I don't understand the GTD "waiting fors".  Why review them all
	regularly?  What I do is, I consider each "waiting for" to be either an action I
	need to take, or nothing in my system at all.  I decide at the beginning how long
	I want to wait before reminding the person or taking any other action in case
	they don't get back to me, and I put a reminder in my tickle file for that date.
	Sometimes at that time I'll change my mind and decide to wait longer.
	If I would do nothing in case the person doesn't get back to me, then I just
	forget about the whole thing, and when the person does get back to me then
	it gets back into my system at that time (e.g. I might put in an action to reply
	to the person again).
If a "waiting for" comes up in my tickle file and I've already received whatever
	it is, I'll remember that, and just remove the item from my tickle file.
	That way, I only need to spend time looking at that "waiting for" once.
	If I was concerned that I wouldn't necessarily remember, then I could
	cross-index in order to remove the item from the tickle file when I receive
	the reply from the person; again I would only have to deal with it once.
What's the advantage of doing it the GTD way?  I would think it would
	foster a feeling of impatience rather than mind-like-water.