Organizing years of photos when folder names have become meaningless

I have years of photos scattered across folders named things like `final2`, `new camera` and `August stuff`. Searching for a particular trip means opening dozens of directories. I want a simple structure I can maintain, probably date plus event, with keywords only for the images worth finding again. Before I reorganize thousands of files, what's the one decision you wish you'd made early: filenames, metadata, folder structure, or a proper catalog?