If you have a habit of constantly biting your lips as they get chapped often, means your body is dehydrated and you need to drink more water.
Dark yellow urine also indicates that it's concentrated and this means that your body isn't properly hydrated.
If you often face headaches, calf pain, muscle weakness and general lethargy, your body is giving you a sign to keep yourself hydrated more.
Lack of water leads to less saliva production, resulting in dry mouth and bad breath.
Poor hydration can lead to dry and scaly skin making it lose its plumpness and elasticity.