"Work up a load until you see pressure signs." Uh, if you don't have the proper lab equipment, by the time you "see" pressure signs, you will be skating about well beyond the case's design pressure limits, and perhaps even beyond the rifle's design limits. That's why they have reloading manuals.
I just gotta find that gunwriter's article wherein he conned White's lab into letting him test a bunch of loads that were just "showing" pressure signs. You know, flattened primers, or flowing firing pin marks, or difficult extraction, or the favorite of the techies, expansion at the base of the cartridge head of more than .00x inches beyond once fired, or whichever witchcraft suits your beliefs. He tried lots of different hot loads, using different rifles and different "indicators", and then Whites Lab pressure tested his loads. Yikes.
And, yup, like you, gentle reader, he had, over the years, gotten away with thousands of rounds using such visual or tactile 'indictors' of excess pressure, always skirting just slightly - a tenth or two below those loads that exhibitted the dread 'indicators'. But, he don't do that anymore. Not after he saw what the pressure lab results were of his supposedly safe loads.
Darned if I can recall which writer, or even which rag, but I do know he was a writer whom I trusted, and who made a lot of sense in a lot of other articles I had read, so I don't think he made s##t up. I know that after I read that, I stick to the book. Now, sometimes I'll admit I cheat and use an old book, which I know does not reflect the pressure behavior of recent manufacture of the nominally same powder, but hey, a favorite load is a favorite load. But all favorite loads can now be found in a reputable manual!