Comment by neogodless

When I discovered this before, I gave it a try and organized my email account.

What I can say is that I like it for helping you choose levels of hierarchy. So far I've squeezed 10 or fewer sub-categories into each chosen category. (I use the 0s, so within 10-19, I start with a sub-folder of 10...)

What I do not do is any of the other suggestions - searching by it, memorizing numbers (though I have an intuitive sense now when organizing email or looking through it.)

I have not tried this folder structure yet for files.