I used to drink them daily. One or two, but four is insane.
I've cut my caffeine consumption down to one cup of coffee per day. All that stuff in the Monsters is _NOT_ good for your body.
I normally sleep 6 hours per night. When I cut them out, I slept for 15 hours nightly for 4 nights in a row, if that gives you any idea what kind of sleep deprivation they were causing. They may not keep you awake at night, but your body never falls asleep deeply enough to do what it needs to do.
But I know, they do taste damn good... and they do keep you very aware and sharp. But as a long-term daily thing I don't think it's the best idea.
P.S. be prepared to take many, many aspirin if you suddenly stop drinking them. It will probably take a couple of days to hit because of the sheer amount of crap left in you
