I've been happily using a Versalab M3 grinder for the past 3 1/2 years, and one interesting thing I've noticed is that the quality of the grind changes according to the speed at which I introduce the coffee beans into the grinder as it is running. If I dump the beans in quickly or all at the same time, there is a lot more resistance (a denser puck) than if I pour the beans in slowly, a few at a time. I'm guessing that this is because with fewer beans, the ratio of coffee to burr is such that the coffee can escape more easily from the grinder as soon as it reaches the correct size, whereas more coffee between the burrs would cause the coffee to get a little more clogged in there, so it may get ground a little more than it needs to as it is being expelled from the burrs, resulting in more finely ground particles and a denser puck. This would also be consistent with the general belief that bigger burrs are better.

As a result of this finding, I set the grinder to a fairly fine setting, but introduce the freshest beans slowly, with the belief that this will give me the greatest grind consistency. As the coffee becomes less fresh (say 6-7 days after roasting), the consistency of the beans begins to change, and I can compensate to maintain my ideal puck density by simply introducing the beans into the grinder more quickly, without actually changing the grind setting on the grinder.

I imagine that this would work with other grinders as well, but of course you can't leave beans in the hopper and do this.

Interesting! I wouldn't have thought that speed of bean entry to the burrs would result in any difference in actual grind quality. My only concern about changing the speed at which you pour the beans in to adjust grind quality would be consistency. Can you consistently pour the beans faster and faster as the days go by? I'd personally prefer to keep the bean entry speed constant and just change the grind setting myself.

Have you tried doing a WDT to establish whether or not it's truly a grind size difference, as opposed to a distribution difference?

I am aware, it's a quite rough and debatable explanation, but the facts are for real...
IMO, if the grind setting remains unchanged, it should be a particle distribution difference;

in several instances, there are fewer fines vs. nominal and boulders, for the same grinder and the same distance between burrs:
- when the burrs are new and less polished - IMO (!): there is more cutting than crushing;
- when the last beans from hopper enters the grinding chamber, or when working single dose; again, the beans being less 'crowded' there is less crushing in the favor of cutting...
or, I imagine, the bean crushing generates most of the fines;
(well, there is a lot about this in this forum, I have to review them...)

interesting enough, the above "last beans enters the grinding chamber" effect, is valid for on-demand grinders;
with doser grinders it is the opposite (!), that is, the last resulting grind has more fines; I mean, when the grinder is left in its terms, and not using a brush during grinding, at the chute, with that clogged grind;

it seems that by controlling the 'flow rate' of the beans entering the grinding chamber, one controls the generated fines...

David, you're right of course, the smarter thing to do in terms of minimizing the fines and maximizing the control would be to always introduce the beans slowly, and just adjust the grinder setting. When I first got the grinder, I did a lot of experimenting to get the best setting, and it seemed like returning the adjustment collar to the same position didn't always result in an identical grind, perhaps because I hadn't yet discovered the importance of the speed at which I dropped the beans. For this reason, I've been hesitant to change the setting since I got it just where I want it, but I should probably just do it. I haven't found it hard to control the speed though, because you can easily hear a difference in pitch depending on how fast the beans are going in and how hard the grinder is working. I have a sense of what it should sound like based on the freshness of the beans, so I just go for that sound. But I know this seems kind of silly.

I haven't felt the need to do a WDT test because my grinder doesn't really have any clumping issues. It falls out of the bottom like powder.

I should probably also do more taste tests to determine whether it is in fact ideal to have as much uniformity as possible, or whether it actually tastes better if there is a little bit more of a range. To do this, I would have to open up the adjustment, but grind the beans faster. The hard thing is that the coffee I'm using (a medium-roast Ethiopian that I buy in bulk) varies so much from batch to batch and a little bit from day to day, so it's hard to make definitive comparisons.

Radu, what you say makes perfect sense and is good confirmation to hear. It's surprising that grinder designers don't seem to take these factors into consideration (e.g. by building in something that would control the flow rate to the burrs) or have decided that speed is more important than consistency of grind.