Let me firstly just say, I'm aware this is a very non-important thread! But I'm curious to see what the norm is out there is mumsnet land.
I shower every single morning before work. At one point this also involved washing my hair every single morning too. However, I started to leave my hair longer and longer between washes using my trusty dry shampoo spray and low and behold - my hair is bouncy, luscious and so easy to style. Volume a plenty! Whether I smell like a Bob Marley wannabe or not I have no idea, perhaps people are too polite to say 
After my hair is washed it's incredibly flat, limp and lifeless and is generally a nightmare to style so I actually hate having to wash it now! But I think I might be starting to take the proverbial for how long I'm leaving it...
How often do you wash your hair? AIB an U dirty scrubber? 