Take Keri for example.  She gets about 2-3 hours of sleep per night.  She's up at 5am monday-friday for work, and she feels like she don't get anything done.  The 5 hour energy drink helps her out tons!  But she realized that it didn't work every day.

With energy drinks a tolerance is built up just with any other chemical in the body to the point that one can handle more of the chemical or it doesn't take effect.  Where 5 hour energy drink is mostly active ingredients are caffeine and b-12, you can take a 5 hour energy drink every day, but it is not recommended.  After 2-5 days you will notice that the effect is not as strong/nonexistent.  Plus your body needs a break, and the b-12 can be taxing on the intestines and stomach at the higher doses as it constricts it.

In conclusion, you can take 5 hour energy every day.  See how it fits you.  Some swear they can take it every day and it works great every day.  But most it won't, so we recommend taking it only 2-3 times a week, spaced out every other day.