We’ve been taking lots and lots and lots of photos these last several years. I manage them with Adobe Photoshop Album and I really like that system. We have them categorized chronologically and that is how I think. I can usually remember what month something happened, and I can usually find the photo that way.
Dan would like them categorized by subject. Makes sense and is logical. But I never put the "tags" on the photos that would label them by subject.