No one is suggesting we under power but the point of knowledge is to be able to make informed decision and be adequate. Not that it hurts to use a bigger cord but like so much n these forums the duty is wayyyyyyy over rated, the demand or load calc. Seems many have a hard time getting past that because they plug in to a 20 circuit it's the load. One of the main reasons for 12 cord is multiple outlets. Very few loads from a single tool require 12. The welders and air comps, even heavy saws come 14. Obviously the longer the more of a factor but I have welded 50 ft 14, even actually measured drop, it's some but in most cases not a great factor.
Another consideration is short circuit requirements but also possible continious duty. I had a comp have a problem where I couldn't see or hear it, the thing would run ok 16/25 but,,, if it stuck on the cord not heavy enough if it had to run constant. In this case it wouldn't have been a big deal but this is a bit about theory and common good practice.
Get no argument from me about door size, bitty doors are problematic and a guy can't pick up and change it. It's also a matter of duty cycle, it's one thing to wedge a car thru a small once in a month or a year but if a guy is driving thru them several times a day a 10 gets tight.
