I have done it both ways...I have handguns that have been fired thousands of times and have never seen a factory round. Sometimes I will buy some cheap factory ammo, just for the brass...not so much anymore, as I have friends that shoot only factory ammo and are willing to give me their used brass.
Rifle ammo is a different thing...I usually only fire a few boxes of factory ammunition through any given rifle in a year's time. So I mostly buy factory ammo...that will soon change, as my teenage son is shooting more and more rifle, especially 7x57Mauser, .303British and .25/06. Die sets in those calibers are on my need to get list. Factory ammo for the 7.62x39 is still so cheap, I can't see the cost benefit of reloading for it yet.
Another thing that may soon change is my reluctance to reload for 12ga shotgun. My son and I have been breaking an awful lot of claybirds the last year or so and even buying in bulk is getting a little expensive. I may need to get a shotshell reloading setup at the rate he shoots claybirds.