If you wore a helmet for just one year ...
Your skin and hair would be filthy. Sweat causes dust to stick. Sticking your head in a bucket of water would make it really gross.
There would be so many insects spiders would take residence. How about a shrew family in your hair. Now your hair is full of shit!
How do you eat? Throw your food in a blender and drink through a straw? No wonder they never show that.