Posted for "Mark Ravinski" <mjrav@comcast.net>:

Bill,
 There are costs.
 Whenever you carry around more fuel than you need for any given flight there
is the weight penalty.  That extra 80 gallons is 480 lbs.  It hurts every
aspect of performance and has bearing on safety too.  Stall margins and glide
speed for instance as well as the more obvious climb and cruise numbers.
 Not to say a healthy reserve is not needed.
 
 Mark Ravinski
 N360KB  1398 hrs

"""
  You can't afford not to, if you value your life!
 
  It doesn't cost any more to buy gas 100 gallons one time versus 20 gallons 5
times!
"""