Beware the Amateur Survey
There is a shaving "expert" who periodically refers to his shaving surveys, from which he draws conclusions such as most DE wet shavers use a three-pass methodology. His conclusions drawn from his data are completely invalid. Why?
Surveying is a science. A key aspect to getting meaningful data from which valid conclusions can be drawn involves having a random sample. In this case, random doesn't mean any which way. It means taking the complete universe of your group to be sampled -- in this case, all wet shavers world wide -- and then using a random-number generator, using those random numbers to select specific individuals from the universe of your group, and survey those specifically-selected individuals. If you don't use this methodology and, for example as the "expert" in question has done, merely post a question on the Internet and allow individuals to respond by their own choice, this completely violates the requirement for a random sample.
Thus the surveyor can no longer say that the results represent the practices of the universe of all wet shavers. No, no, no! All the surveyor can say is that out of the X number of respondents, Y percentage said they preferred (or did) whatever.
So when you hear silly claims that most DE shavers use the three-pass-shave method (WG, XG, then AG), this claim is to be taken with a grain of salt, not as any meaningful truth. No way, Jose!
Alum as Shave Indicator
Although some wet shavers may slavishly smear their wet post-shave face with an alum block as an indicator of whether they had a good shave or not, this is a silly practice. And worse is those few who don't immediately rinse it off! If someone is promoting the general, daily use of an alum block as a shave indicator, they are trying to sell you some, or are just misguided.
Alum is a dessicant, a drying agent. It does sting on wounded skin. However IT'S A DESSICANT, which may not be the best treatment for any skin -- anyway, that is, skin that you don't want to encourage to become leathery or wrinkled.
I would suggest using alum not as a shave-quality indicator, but rather to spot treat very minor wounds such as pin-point weepers that aren't clotting quite quickly enough. For more significant wounds, a styptic pencil may be called for, which is also a dessicant, but which is more powerful than alum.
Brush-Movement Patterns while Lathering One's Face
I've seen several videos suggesting (in a jocular way, not with great seriousness) specific brush-movement patterns such as a figure-eight pattern, while lathering one's face. This silliness is certainly ridiculous and borders on nonsensical. I feel embarrassed for the person mentioning this topic (of brush-movement patterns) in his videos. To him: JUST STOP! To you: ignore this silly advice.
The Clogged DE Razor
I see and read mentions of DE razors requiring rinsing because they become clogged with lather and stubble. I don't know about you, but I've many times -- essentially every day -- have had a DE razor filled with lather and stubble, and have rinsed it out because it was becoming messy. However, I've NEVER had a DE razor clogged with lather and stubble to the point that its ability to shave is in any way impaired.
Lather isn't ground raw potato, which I've seen clog the drain plumbing downstream of a kitchen sink's garbage disposal (yeah, Mom, I'm talking about you!). I've never seen lather clog a razor -- merely fill it. Let's get real. ;-)
Shave Like Grandad
There's this blog called Shave Like Grandad that says silly things all the time. (There are lots of good things too!) In fact, the silly things in Grandad are so numerous that I'm overwhelmed just trying to come up with a short list.
So the bottom line remains: question everything. What someone believes and touts may simply be patently not true (such as the "expert's" conclusions based on his surveys), may be true for some but not necessarily for you, or may just be down right not worth mentioning.
Happy shaving!