sashmo

I have over 3,000 photos in iPhoto. In the past, when I didn't have so many photos, I would organize photos in folders, along the left side. Then I get so many folders, (and iPhoto won't sort them alphabetically) I need a search, which isn't available, for my folders. It had been recommended that I add keywords to every photo. I've started doing that. But so many photos! I'm wondering if it's worth it. If you are an iPhoto user, could you tell me if you use keywords to organize photos? Should I keep marching, adding keywords to each photo? Thanks for your advice.