Firstly, as we won't be washing away the oil produced naturally by our oil glands, dry hair will be a thing of the past.
Secondly, as our hair traps moisture, it leads to the collection of bacteria. No washing might result in foul smelling hair. Also, lot of exercising might lead to an early onset of foul smelling hair.
Thirdly, washing of hair leads to wearing out and fading of hair color. So, no washing of hair will be good news for those who have just had their hair colored.
Lastly, your scalp skin might not be happy as no washing means huge accumulation of dust and dirt.
On the flip side, some experts believe that no washing might actually improve the quality of your hair and make them look incredible.