No matter how much you don't feel washing your hair tonight, do not substitute a real shampooing with dry shampoo. It's not the same.
More importantly, if you ignore this warning, leaving apathy and human inertia to dictate your level of personal hygiene, please at least use a quality dry shampoo. Do not, for example, substitute with a dry shampoo designed for dogs because that is all you currently have on hand.
While dry shampoo for dogs does a passable job of making sure my wet dog smells a little less like a vile combination of damp moss and old deer carcass, it made my hair smell like a wet dog. And to add insult to injury, it had the audacity to do nothing to improve the overall look of my hair or act as a stop-gap between actual washings.
This was not the easy fix that hair commercials everywhere promised me (slow-mo hair flick)....that said, maybe I'd have done better watching dog groomers commercials instead?