I drink probably a full pot of coffee per day. I typically have less problems cutting back on my coffee intake during spring/summer though. lately i've started taking a vitamin D pill and acai, so I will try to cut back on my coffee intake and hope that those two pick up the slack for me. The short winter days really wipe me out.
in 8 or so years of heavy coffee drinking I have noticed two things.
a. keeps ya regular

b. I need to drink a lot of water after drinking coffee to hydrate myself enough for working out. otherwise I puke.