It has been many years since I've taken stats, with a whole bunch of things that I don't remember anymore. One thing that I have experienced though is that the rolling stats at 10 data points, 20 data points, and 30 data points can be different - sometimes significantly. Granted, we can argue progressives vs weighing each charge; centerfire vs rimfire; light recoiling vs "I can't shoot 30 uber-magnums in one sitting," etc. You may need more or less data points for your own confidence interval depending on how consistent you know your handloaded ammo to be. There have been times when after 10 or even 20 shots, I thought I had an excellent set only to find that the average caught up with me by the time I got to 30 data points. If I would have stopped at 10 or 20, my conclusion would have been different than going the full 30. Call me old fashioned, but I like 30 data points. After "about 30" you've got what you've got. Going to 40 or 50 doesn't change a whole lot. But, in some applications - like a known, handloaded precision rifle load or a hard -recoiling caliber, some may call 20, 10, or less data points good enough. What the shooter is looking for is reliable information that can give a basis for comparison. While nobody gets a trophy for having the lowest SD or ES, those descriptive statistics can help shooters choose consistent loads. The tale of the tape after all is the target, not the stats. Remember, the stats and the targets don't always coincide. Which is why one must consider the stats, but also harmonics, twist rates, barrel preferences, etc.