The way I recall measuring a true BBS shave was the cotton ball test as well. Now, I get close shaves almost every day (8 to 9 out of 10), and great shaves (9 plus out of 10) many days, but rarely could pass the cotton ball test in every nook and cranny of my aging countenance and saggy neck (10 of 10). It's wonderful when it happens, and I did shave to that level consistently for a while and rarely had much irritation. That happened after working on perfecting all my technique, whether a DE, SE, or straight was in hand. In technique, I include proper lathering with a good cream or soap, and the pre and post shave items. I just try to do the best I can each day with a reasonable amount of effort while focusing on the highest possible enjoyment level and removing as much stubble as comfort allows. I've learned when irritation is looming and that's the point I wrap up the shave and call it a day; there will always be tomorrow until the day there isn't.The one variable in the BBS chasing is that everyone's skin and stubble are very different. Some people have well behaved stubble that goes in a consistent direction for each section of their shave. And for those people, yes, good prep and proper technique can yield a BBS on a regular basis. However, for me, i have a couple of spots on my neck where the hairs swirl in a circle pattern, and lay flat to the skin in some spots. I have been at this a long time. I have a lot of high end and vintage razors. And I know how to prep and practice proper technique. But there are just those days where no matter how hard i go at it, and no matter how much I buff and j-hook and work all those trouble spots, I cant get them totally clean. So even though I get a BBS result on 95% of my face, I normally will still have a few little rough patches when I rub against the grain in those trouble spots. When I measure a BBS, I use the cotton ball test. Take a cotton ball and rub it on your face in all 4 directions. If any cotton gets pulled, even a little, its not a true BBS result. Every once is a while, all the stars align, and I can get a true BBS. One way to potentially get there for me is with a Charcoal Goods Level 3 razor and a really sharp blade. But I can not use that all the time, as my skin will get sensitive to multiple uses of a razor with that much blade feel. So do I chase the BBS? Not every day. But, I have been know to spend lots of time and money in the pursuit of it. Do I care if I dont get it? Not really. But when I achieve a true cotton ball tested BBS, its a thing of beauty, because it is such a rare occurrence for me.