There is some implicit training in this process; by the time you have created "very old" and "<last year>" you are on the way to sorting things slightly better than you have before; or getting a perspective on "things that have expired or passed". I almost certainly didn't explain that very well.

I can't teach to (2) other than to say that after the activation energy (of setting up the system) it's mostly gone from every-day experience. As for (1) - dealing with things; and having a minor sorting system makes it easier to realise how much there is/isn't. and can help you actually get a handle on it.

Does that help?