I have naturally dry hair. Really dry hair and the single most beneficial thing I have done for my hair's health is giving up shampoo. Yes, I have given up the soapy, lathery, suds that most people think are requisite for clean, beautiful hair. My mom always taught me that my hair wasn't clean until it squeaked. Um sorry mom, but that was terrible advice. If your hair is squeaking it has been stripped of all its beneficial oils. And that is no good. Aside from that, most commercial shampoos contain a whole lot of harsh and or toxic chemicals we would be better off avoiding anyway.
If you need an alternative. Try my favorite, apple cider vinegar. It cleans your hair and it gives fantastic shine. I mix about 1/8 cup ACV with about 1 cup of water in a squeeze bottle in the shower, squirt it all over my hair, let it sit about 5 minutes and rinse. Follow with conditioner and style as usual.
For more details and alternatives read Why You Should Go No ‘Poo by Christi Colvin.