Posted for J H Webb <airmale@alltel.net>:

 IF you properly plan your flights like a professional pilot you will find
some use for them, but only minimal usage. They are nice on landing as you can
reduce your landing roll by about 200' by the reduction of some of the lift,
transferring weight to the wheels and the additional drag.  They are not
needed to slow down for the traffic pattern if you reduce to approach power
(about 16" HG) in level flight between 8-10 miles from the airport.
    Using them as a partial lift reducer, they also help keep the upwind
 down on crosswind landings, much as airliners use spoilers as lift dumps.
    No, they are not really necessary but I like them and they are useful.
 
 Jack Webb
 L360, LIV