I'm a strong advocate of record-keeping, something not enough writers seem to do. I believe writers should know exactly where they've submitted a manuscript, what the response to it was, and, if accepted for publication, what rights they licensed to the publisher and for how long.
I've met too many writers over the years who didn't and don't keep good records. They resubmit stories to publications that have already rejected the stories, submit a manuscript to multiple publications at the same time without realizing they've done so, and don't know what rights they've licensed and so have no idea which rights they still control.
So, I have a copy of every contract I've ever signed.
I became a professional writer back when we all used typewriters. Photocopiers were expensive machines owned by businesses, not by part-time writers working in their spare bedrooms. To make a copy meant sneaking copies on the copier owned by our employers or driving into town with a pocketful of change to use the over-priced and poorly maintained copier at the grocery store.
The same went for faxes. Fax machines were office machines and, on the rare occasion when a writer needed to fax something--publishing moved much slower then and most business was done through the U.S. Postal Service--the fax was sent surreptitiously from work or from the local print shop.
I was ahead of the curve.
I owned a fax machine.
And my fax machine had the ability to copy.
So I copied all of my contracts, using my fax machine, before returning the originals to publishers. Without leaving home! Without having to look over my shoulder at work!
On thermal paper.
Thermal paper fades.
And I now have several blank sheets of thermal paper in my files where once I had copies of my contracts.