Rifle cases, except very short ones, usually have a length tolerance of -0.020" from maximum. Most case trimmers and manufacturers aim for the middle of that range, which is -0.010" from maximum, to have ±0.010" wiggle room.
When the case is fired it expands to fill the chamber. When you size it back down, the expanded diameter is squeezed by the die, flowing a little of the brass rearward, but mainly just drawing the whole case longer. The shoulder portion of the full length sizing die then pushes the lengthened shoulder back in place. The excess brass from that part of the sizing has to go somewhere, so it flows forward into the neck area.
So, how much will your case grow? Well, how much wider and longer than the sizing die profile was it when you pushed it in? Is your die on the large side of diameter or small side or even a small base die diameter? Those are the main factors that determine growth during resizing. If you never squeeze the case back toward original diameter (neck sizing only) you may never see significant growth. If you full length resize, but your chamber is tight, growth may remain quite small. If your fire at modest pressure levels the brass won't stretch as sharply into the chamber profile and will grow less than a maximum pressure load will, so it gets squeezed back less during sizing and grows less. If you fire at peak pressures under about 30,000 psi with most powders, the case backs up in the chamber rather than sticking to the chamber walls, so there is no stretching at the pressure ring, and that means they may need very little shoulder setback and don't grow appreciably.
In the extreme, you often see low pressure straight wall pistol cases actually shrink with each resizing because they backed up into the chamber, were blown out shorter and fatter rather than stretching, and during resizing the amount of brass flowed rearward exceeded the stretch back toward original length. I once tracked a bulk purchase of .45 ACP cases through 50 reloading cycles with light target loads, and at the end, the ones that hadn't split at the mouths and been tossed or hadn't been lost to the range gods were all about 0.025" shorter than what they started out with. A loss of about half a thousandth per load cycle.
On the other hand, I used to get an average of about 0.005" growth after resizing .308 rounds run through my M1A. But I would get a few that grew 0.007" and a very occasional 0.010", and a few that seemed not to grow only a thousandth or two if at all. These were same-brand cases first fired in my gun and having the same load history thereafter. Back then I didn't have the tools I do now, but if I had, I expect I'd have found the long ones were light or had uneven wall thickness so the thin area could fill the chamber more tightly. The ones that didn't grow may well have had the brass flow into the body and shoulder junction more than the neck, perhaps due to inadequate lube on the shoulder during resizing. They may also have been heaver and more uniform than average so they had more spring-back in the chamber. There are a multitude of possible explanations for why one case stretches more or less than the next.
The bottom line is if you are full length resizing, you want to check every case with a gauge or a caliper after resizing so you find the outliers. Don't measure just a couple and count on them all being the same. If you want to crimp you may have to trim every time to keep the crimp pressure uniform.
If you need speed for trimming a volume of cases, there are a couple of motorized routes. The Gracey trimmer has been around the longest and works just fine.
The Giraud is the Cadillac in terms of construction, with ball bearings and the like and a bigger motor. These two trimmers do two things most others do not. One is they set trim length off the case shoulder, which eliminates the step of having to put the cases into some kind of separate holder. The other is they feature custom shaped cutters that chamfer and deburr the cases simultaneously as they trim, eliminating the need to perform those two additional operations.
There are a couple of less expensive trimmers that register off the case shoulder head, the Possum Hollow Kwick Case Trimmer and Little Crow's WFT trimmer. The first may be adapted to a drill while the second requires a drill. Neither does simultaneous deburring and trimming.