If you want to form the habit of checking it, the REAL habit to form is putting everything in it. If I get to work and there NO PAPER ANYWHERE for me to process, that's a pretty good reminder that I need to pull out the tickler file.
Tickler files come up a bunch, so by doing a search, the new user could come up with a bunch of ideas.
I want to share something I have not seen in all those posts (not that this is what I do, because it's not), but it is interesting. This author
http://www.leadingauthorities.com/12045/Greg_Vetter.htm recommends the following: Use your 1-31 files for ONLY the items that are specific to that date--in other words, the things that can't be done until then and must be done on that date (like the tickets to the concert or the driving dorections for the trip you are taking that day). In front of the 1-31 folders are: 5 folders (labeled 1-5) following by 3 folders (labeled A,B,C).
The dance consists of processing incoming papers into an A, B, C (yeah, I know that anti-GtD, but I'm just the messenger here). You then work from the A folder. Look through the A folder and select the first 5 items to work on and drop them in the those first five folders (numbered 1-5). When those are done, you go back to the "A" folder again. When it's empty, start working from the "B" folder. At the end of the week, you examine the A, B, and C folder and re-evaluate it all as far as what is each letter for the next week.