I trim on the first reload and every reload after that. My Giraud trimmer makes trimming a snap, I will buzz through 88 cases in less than ten minutes from the time I go find the thing to when I put it back up. I figure it takes less than five minutes once I start trimming. It is as fast as a pencil sharpener.
I learned decades ago that long cases will blow primers.
Incidentally, I trim to 2.000". Too long is a safety risk as the neck will pinch the bullet in the throat but too short, as long as it holds the bullet I don't know what too short might be.
If I'm not shooting, I'm reloading.