had best (do something)
should do something, ought to do something
I had best go home soon as I want to get up early tomorrow morning.
Reasons You Should Brush Your Teeth
Smoking is bad for you but smoking and not brushing your teeth is bad for you. It s not just the smoke in your lungs that can cause Chronic Obstructive Pulmonary Disease, but also the tobacco destroying your gums. Like a double edged sword it increases your chances of having COPD twofold.