There are a lot of things I don't wash often in the interest of preserving them. Not in a disgusting, never-cleaned-my-sheets way, but any woman who has owned a perfect black cardigan or a silk jacket probably knows that the harshest thing you can do to your clothes is wash them. I'm a firm believer that some people wash their clothing far more than the need to and without nearly enough care. Then again, there are plenty of people who could probably put their jeans or sheets through the wash a few more times per year to great effect.
Besides clothes, one of the main things I do not wash all that often is my hair. This has been in the news in the past months, most notably in this article, which has a snarky and misleading title. It's mostly about women who eschew most at-home hair care in exchange for weekly washes and blowouts. I actually used to be one of these people, long before it was a mainstream trend, because it's a very common practice for the "control" of "ethnic" hair. Bloggers responded in many different ways. Some were repelled by the prospect of rarely washed hair (offensive!), some admitted that they weren't diligent squeaky-cleaners either. There was definitely some confusion on what constituted not washing one's hair (the Times implies it's someone else washing your hair in the salon, perhaps once a week).
For me, not washing my hair means massaging my hair/scalp with conditioner daily, and rinsing thoroughly. The only step I omit is the use of harsh detergents that leave my usually soft curls feeling pretty wiry. I wash my hair either when I get it trimmed at the salon (every six to eight weeks) or if I perform some activity that I feel has left my hair pretty dirty (swimming in a chlorinated pool, for example, or visiting a smoky lounge with my friends). My hair is not naturally greasy, in fact, it's a bit dry, especially when harshly treated with detergents and harsh stylers. For years, hair care professionals have told me that the best way to deal with dry hair, to keep it healthy and strong, was to stop washing and it turns out they were right.
It doesn't hurt that in a quest to get my hair healthy I cut it short (getting rid of some ill-advised highlights) and reduced heat styling to about once a month, but I don't doubt that limiting washing gives the oils in my hair a chance to do whatever it is they do. This is definitely not what most people want to hear, but in the long run it's probably better to work with whatever your natural texture is, unless you want to be one of those people wandering the mall with really frizzled out hair.
I'd ask if you wash your hair everyday (or at all) but I'd hate to start another argument...