However, if I understand correctly, the only metadata that exist now with each picture would be camera, lens, exposure, date etc information. I can add information like Christmas 2001, etc but I would have to find and enter that information on each picture. With Aperture I was able to group picture in events/folders. It feels like a daunting task to go through 8,000 images To add specific metadata on each image.
I think I said you don't have to do that ... specifically about your statement that you wanted to find all pictures from a certain year, but if you already have meaningful folders, you should use those. no need to do do unnecessary work