John Howard Loc: SW Florida and Blue Ridge Mountains of NC.

When LR updates it sometime creates an update for the .LRcat file as well as the other related files such as helper, preview. I am wondering it it is best practice to delete the old files. My LR Settings folder on my external drive is not a large file but getting pretty messy with all the old files not used. And now LR has added in addition to the -2-3 a v10.

via the lens Loc: Northern California, near Yosemite NP

Yes, deleting the old files is the best practice. This is assuming you have a recent backup of the catalog, just in case something goes wrong.

DWU2 Loc: Phoenix Arizona area

If, by update, you mean that Adobe has come out with a major revision of the software that requires changes to the format of the catalog file, then I would say hold onto the old catalog file for a while until you are sure that the new version of LR is stable - I don't think you can do a rollback to a prior version unless you have the old catalog. However, once you are satisfied that LR is stable, there would be no reason to hold onto the old catalog.

On a related topic, my LR (Classic) is set to create a catalog backup on exit once a week. So, those .CAT files pile up. You might want to go back to an old catalog due to file corruption. The problem could have existed for a while, so there's a trade-off between being 100% positive you can roll back far enough and taking up space. Plus, the farther you go back, the more edits you lose. My choice is that I usually keep 3 .CAT versions.

Ron 717 Loc: Pennsylvania

Whenever I have a catalog update, I keep 2 of the most current catalog backups and remove the rest, this in case I need to revert to an earlier version of LR. Although I have never had to do so so far.

BobHartung Loc: Bettendorf, IA

Just delete them. I also rename the Archive so I don't get the 2-2-3-3- etc.