Owning your own extractor, even if you have only one hive, lets you
rob, extract, and give back the next day.  It lets you take advantage
of a lucky break in the weather, or in your schedule.  I use an old
two-frame reversible-cage model, and my wife loves the mess in the
kitchen.  Being able to give the boxes right back means we don't
need as many boxes, and extracting two frames at a time means we
can separate the different flavors of honey in an interesting year.
 
jimo