What do you do when you have 3 dimensional physical items that are either needed in the future or that the decision on will be deferred?
They can't fit into the tickler file as they are things not papers.
A current example: I have some sample ear tags that I will need for a small ruminant seminar we are hosting in July. I don't want to lose them yet I really don't need them sitting on my desk until then. They are small enough that they can easily get buried or lost under papers yet they would puncture holes in the folders if I stuffed them into the ticker file.