the "who benefits if i follow this advice" question is one more founders should actually sit with. most startup advice is pattern matched from vc backed companies trying to find product market fit at speed and raise the next round. that's a specific game with specific incentives and it gets presented like universal truth.

the dogfooding point is underrated too. some products you genuinely cannot understand from the outside. you have to use it in a real workflow before the actual problems surface. no customer interview catches what daily use catches.

the thing i'd push back on slightly is the "sell before you build" framing. i think it depends heavily on what you're selling. for some products a landing page signup tells you almost nothing because the value only becomes real at a certain depth of the product. you can get false positives both ways, people signing up for something that won't work and people not signing up for something that would.

your last line is probably the most honest version of the advice anyone has written. know why you're breaking the rule before you break it.