Yep, you have to. I have ... lemmesee... one full-length blue glacier-print one, one Mayan-print lighter blue one I've chopped in half, (those are my favourite winter ones), one full-length black one with yellow Chinese? characters (that's my Ninja one for pulling up and down over my face ), one least-favourite dark green leaf-print one that I've cut a hole in for actually wearing over my nose all the time and one lovely orange brown Lascaux cave print one that I've cut in half (favourite autumn one). I guess that makes 5, or 7 if you're counting halves...

I have a thing for the National Geographic ones, and have spent a while finding the ones I like.