On whether we're talking pistol load development or rifle load development.
For pistol, where there is so much room for the human element, I like Cheygriz's idea, and do about the same. If I had access to a Ransom rest for the pistol in question, I'd do it like I do rifle.
For rifle, where I can benchrest it and all but remove the human element, I use one 10-shot group for each change I make in a load, going up or down by 0.1 grain of powder (VERY carefully measured!) if it's powder I'm changing. For something as important as which load to use for the once-in-a-lifetime buck, 3 shot groups or 5 shot groups don't tell enough. Oh, and you have to let the bbl cool sufficiently between shots. Every shot you take while hunting is with a cold bbl.
God Bless America