I generally use a bit out dated film. If it is old, I keep it in it's original packaging, and display it in my glass display case, along side the cameras of the same era it was made and used.

I used to keep old packaging, and display it after using the package contents. Then I thought this was a bit too close to the line of hoarding.

Now I limit myself to a mostly hidden stash of packaging.
I flatten a 35mm cassette after removing the end caps, and toss the flat result into a small box.
For 120/220 films I save the backing paper at either end and tape it onto the extra carboard backing from 8.5x11 design paper pads that I collect as I use up these pads at work.
Some day in the future I want to show someone the number of different film types and vendors that once existed in the film marketplace.