Most folks here try to stick to a one catalog approach as it offers better use of things like Collections and searching. If you do not remember a lot about a photo, having many catalogs negates a lot of the search features that LR Classic offers. Yes, there are times when separate catalogs are needed, so this is not an absolute approach. I have my primary catalog for my personal work, and then have a catalog for work that I did for a nonprofit agency for approximately 10 years. Those photos were very limited in how they could be used, so it made sense to have them in their own catalog.
Post if you have more questions about this, but I would first search as you will find many threads about this subject.
Good luck,
--Ken