To reply directly to the OP, there was a time I made a keyword for each file printed giving the date it was printed (e.g. "ptd170702") but I came to find it cumbersome to continue to do that.
In my current workflow, every time I “finish” work on a file (i.e., print it and store the print in a box as well as possibly add it to my website), I add keywords to the file to help me retrieve it.
I use kw=“done?” (the “?” because we can always go back and change something!);
I use kw=”boxed”;
I use a keyword to show the paper size of the print, and another keyword to show the image size on that paper;
I use a keyword to show which box among the many I have contains the print in question;
I use a keyword to show that the image is on my website.
Of course, the files have whatever other keywords were appropriate to them.
I print from both Lightroom and Photoshop. When I make a snapshot in Lr corresponding to the date of the print, the snapshot begins with yymmdd. When I print in Ps, I make a layer comp (again beginning with yymmdd) so I have a record of the version of the file that was printed.
There’s more to it than this (e.g., my use of smart collections and collections as well as stars and other keywords to show files “in process”) but I hope what I’ve described above helps.