Perhaps others experience more variations in case length than I do, or perhaps I'm just more tolerant of minor variations in case length. I don't know. I have thousands of 38 Special casings (and thousands of other types too) and I can't remember the last time I trimmed a handgun casing. I have done it, but it has just been a long time since doing it.
I enjoy reloading as much as I enjoy shooting, so the work isn't the issue. I just don't find trimming handgun brass to be productive.
There have been occasions when I strived to produce incredibly consistent ammunition. Going through steps such as sorting brass by manufacturer, squaring primer pockets, de-burring flash holes, trimming casings to a uniform length, seating primers off the press, weighing each powder charge, culling bullets by weight and only using bullets that fall within a narrow weight range. While those measures can reduce group size, they don't reduce the group size enough to be significant.
If I was loading say, 50 rounds a session; I might consider trimming casings. Reloading is a hobby and if you enjoy the task then there is no harm in the extra labor. In fact, there may even be a great deal of pride and satisfaction in that labor.
However, I load handgun cartridges by the hundreds and I don't see the need (or benefit) of trimming handgun brass. No criticism for those that wish to expend that extra effort.
Hypothetically speaking, if trimming cases reduces your group size by say 5% but practicing more often reduces your group size by 50% (and I'm just making up numbers here) then under those circumstances it becomes far more beneficial to produce more ammunition as opposed to producing extremely consistent ammunition.
