Trimming is probably not necessary for most cartridges, particularly custom barrels with alpha brass and good handloading techniques.
For other types of barrels and brass, especially range pickup 223 or for just starting with a consistent baseline case length, it's so darn easy to trim to max length every time with the $25 Holub Machine & Repair World's Cheapest Trimmer trimmer or the $75 Little Crow Gunworks World's Finest Trimmer with inserts type cutters that fit on your cordless drill. So fast and easy! The Little Crow trimmer has changable inserts for multiple calibers but it's a minor pain to re-set the length every time you change to a new caliber/cartridge. Better off buying one HMR WFT trimmer for each caliber and set it n forget it for simplicity. Purchasing 3 HMR WFTs is cheaper than most hand crank mini-lathe trimmers.
Trimming by hand, one at a time, on a hand crank mini-lathe, is a pain in the [beeep] and takes forever. Plus they are expensive. This was my least favorite chore. Glad I ditched ghis method for something SO MUCH faster and easier.
