Bigcountry, I agree you don't have to trim each time, but I've been reloading for over 40 years and consider it a hobby and I don't mind trimming. The RCBS Trim pro is easy to use and fairly fast. And a lot better than the old Forester I had. That was a pain in the butt. The reason I trim is to make each case as uniform as possible. Of course when I do load, I usually load a minimum of 100 rounds at a sitting. Except when doing load development.
Just about everything I shoot except rimfires of course are reloads. The only thing I shoot factory ammo out of is my Mini 14 Ranch rifle cause I can get the Wolf ammo cheap, about $3 a box and let 'em fly.