I have several bandanas of several fabrics, sizes, colors, and patterns.

I have the following uses, depending on the fabric (which varies by season):
It's a muffler to keep out chill winds
It's a pad to keep my shoulder-carried canteen from chafing my neck and shoulder
It's a moderately successful filter for dust and sand in windy places
It's a face-covering if I'm really being blasted by sand
It's a head covering if my hat disappears and I need sun protection
It's a sign of love and caring - my wife says I look good in one she made for me
It's a signal device - light-colored ones can be seen waving through tinted glass, e.g.
It's a potholder
It's a sling - some of my bandanas are a yard square
It's a gauze pad
It's a compression bandage
and on and on.