Well, I spent most of my life out in the desert without a hat, and of course, now I'm paying for it. Once a year I go to the dermatologist and she either burns or cuts off the skin cancers.
There are really 2 types of hats for me: the
tilly hat, with a brim all the way around, or the
visored hat with a flap in the rear. Both look dorkey, but it beats skin cancer. Those links above are only to give you an idea. The tilley/brimmed hat obviously comes in a bunch of styles (rainproof, straw, etc) as does the visored cap. Shop around.
That said, when cruising, we'd get a lot of lectures by doctors about sun exposure (thataway/Dr Bob will be here soon,) and one of the most important statements is that a hat isn't sunproof, but about SP75. So try to use sunblock as well. The brimmed hat has a thicker layer of cloth covering the ears, but doesn't cover the neck as well (hence the term "redneck".)
Whatever the style, wearing a hat has helped tremendously.
Boris