I have a bad habit of getting dehydrated when I go for long rides because I don't plan to ride as long as I do or I just don't force myself to drink on the trail. Trust me, you don't want to get dehydrated. When I do I get really bad headaches and lose my energy. It can sometimes take a full day out of me just recovering. Don't worry about drinking too much; worry about not drinking enough!

(electrolytes, too!)