From the GTD book: "To manage actionable things, you will need a list of projects, storage or files for project plans and materials, a calendar, a list of reminders of next actions, and a list of reminders of things you're waiting for..."
Of course, the beauty of the system is that you can tweak it any old which way, and of coruse the tickler is a great place to put things you're waiting for that you don't need to see until a particular day.
I find the list allows me to check in and see if I've been waiting for too long, and then I can nudge as appropriate.
For me, the purpose of Waiting For is when I am waiting for something (from a person, the season to change, a new product to be released, etc, etc) and I do not know when it will be done.
If I put the reminder in my tickler for next month and it gets done next week, there is a potential disconnect with finding the original. I absolutely use the tickler where it makes sense. For example, if I want to be reminded of something on a certain date or I know I'll want to follow up with someone on a certain date if it isn't done.
As examples, my current Personal waiting for includes a list of books/movies that I've lent/borrowed, buy a new lamp when Ikea opens, call my Aunt to invite her for dinner to celebrate when we've sold our house, and several online purchases I've made for which I'm waiting for delivery.
At work, I've got drafts that I've sent up to my boss, specific training/experience I'm looking out for for my staff, meetings I've requested, etc. By having these in my list, I review them regularly and can identify if I need to follow up with something.
You could do the same with paper in a tickler file but I find having this list integrated with my system invaluable. I often frequently alternate from NA to Waiting_For and having it in my system makes this very easy.
I am waiting for a response to my e-mail regarding USDA official ear tags. I have no clue when the government folks will get back to me so waiting for is more appropriate than a tickler. Reason is when they do get back to me I need my notes and info for that project to set my next action. If I tickle it and they get back to me sooner than I expected then I have find where I put the tickler notice and that's a PITA. if they are later than I tickle it for then I have to move the item forward day by day. I hate that and will tend to even avoid looking at my tickler when I have a lot of things that are oh not today maybe tomorrow items in it.
Oogie McGuire - Mac, iPhone & Omnifocus
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Paonia, CO USA