Stop using soap years ago and my bacon grease does the work now.

Have you ever stood on a black asphalt street with no trees at 3pm in July and then walked one block over into shade? The difference hits you right away, it is not some small thing. Those shade maps come from actual temperature readings, so 8 to 10 degrees is real, not made up.

My old foreman carried a roll of masking tape in his pouch every single day and tagged every tube in the bank before we touched a torch, must have been 200 tags on one job in Texas City. That tagging step is what your uncle is really talking about, the layout guy walked the floor and marked each run so the welders never had to stop and read a print 40 feet up. When you skip that and just work off the drawing, every fitter ends up solving the same puzzle alone and you get tubes fighting each other at the header. Cutting tags takes maybe a day of one guy's time on a big bank, and it saves that back ten times over in rework and grinding. The old timers weren't smarter than us, they just knew a print in your hand up on a scaffold is useless compared to a mark on the steel.