Make sure you are actually using your EC2 reserved instances

An example of the output it produces:

  Comparing reserved instances to running instances...

  m1.large:
     us-east-1b 1/1
     us-east-1c 1/1
     us-east-1d 1/1

  c1.medium:
     us-east-1a 4/4

  m1.small:
     us-east-1a 1/0

  --
  0 unused reserved (good)
  1 unreserved running (bad)