Dry shampoo coats the hair...over time it will cause build up because the point of it, is to clean the hair with out soap and water when it's unavaible or for any particular medical reasoning their may be....not limited to by choice.
The idea behind dry shampoo is to remove excess oil from hair follicles without having to actually wash the hair using a traditional shampoo and water. It is not unusual for households to keep a small amount of dry shampoo on hand as part of an emergency hygiene kit. In the event that water is not available, the dry shampoo compound can be applied and provide at least a partial cleansing of the hair.
-wise geek
and no I don't use dry shampoo but was taught all about it back in cosmo school...this is one of those, it's to each their own.
Just remember, at some point, you may want to use water and possibly poo. Co washing, oil washes, rinsing with water only...there are many ways to clean your hair, even if you decide to use salt water, salt cleanses the hair and many on here love to use baking soda and water instead of conventional poo. The options to poo is limitless!
---I've used sea breeze...it makes the scalp itchy when applied but it strips the oils and build upfrom the hair and scalp. It leaves my hair feeling clean for a day or 2 but I found that using EO's works best!!!!