Hi everyone,
I was wondering how often you recommend checking the length of pistol brass to see if it needs trimming. Do you check it every time before reloading and check every case? I think that would be time consuming, so I am looking for the most efficient way from the experienced people on this forum.
Also, how many times do you find that you can fire base before it needs trimming on the average?

In 45 plus years of reloading who knows how many tens of thousnads of pistol rounds. I hardly ever worry about over all length of pistol cases and never trimed one.

45acp, have never trimmed one. 44mag, needs trimming now and then. Mostly to get a good crimp, as brass of a different trim length does not crimp the same. Range brass of all different headstamps will grow at different rates, check each one. New brass of the same lot, only check 10 out of 100 for length, as they seem to grow at the same rate.

I have worn out or split the brass before I have trimmed it 32S&W-380-9mm-38/357-41-44-45-44/40.

I been loading for the 44 magnum and 45 ACP for a long time and never remember having to trim a case.

I will go through new brass to make sure they are all close to the same length.

I have never trimmed any of my pistol brass. Never had a problem.

Just a point on terminology.
CL is Case Length
COL is Cartridge Overall Length

"Overall" denotes an assembly.

That said, in the last 35 years the only times I've "trimmed" pistol brass was when making 38 Spl out of 357 Mag, or 380 Auto out of 9mm Para.

If your really worried about it, make a simple "Max CL gauge" (2 pieces of flat stock, a piece of tubing filed to the "max" dimension and a bolt to hold it together (or just lock your caliper at the max length) and any case that doesn't slip through the gauge needs trimming.