How do you organize years of photos with terrible filenames?

[Nefetiti]

I'm finally sorting through several years of photos and most of them are still named things like IMG_4832, DSC_1029, etc. There are thousands spread across different folders and devices. I was thinking of renaming them using the date plus maybe an event or location, but doing it manually would take forever. What naming system do you use for large photo libraries, and has anyone found a good way to automate most of it?

[Nefetiti]

Small update: I've been testing a few ways to handle this and ended up trying a batch file renamer for the bulk renaming part.
The approach I'm leaning toward is something like `YYYY-MM-DD_event_001`, while keeping the original files backed up separately. For thousands of photos it seems much more practical than renaming everything by hand.
Still curious if anyone here uses a different naming convention that works better long term.