I get at most 6 hrs which is good for me. The "AT MOST" part bites. 3-4 is avg and sometimes I take a 20 min nap instead of a break. The caffeine in Dt Pepsi has to do the rest. I have a seperate MOH* that I keep at work just for the occasion. Its a good thing that Wallymart has 2 litres on sale this week $1 ea. there are 15 in my trunk at the moment. Did I mention I'm a DietPepsi-holic?