While I can see how principles 7 and 8 could help most people, they wouldn't work for me. Every purchase of an item I intended to use long term (2 years or more) was preceded by anywhere from days to weeks of research, reviews, and comparison shopping. It's a huge brain drain, but it was worth it. I now have 98% of all possessions I'd want, with the remaining 2% having not reached the right opportunity yet (I'm also…
I'm young but I try to have this same approach of taking the time to buy nice things which will last (furniture, kitchenware, camping gear), and tend to be a bit obsessive about ratings + reviews. I sometimes wonder if this is the "right" approach or if I would be happier buying cheaper crap and spending less time doing it. I do find strong intrinsic value when I'm confident I bought the thing which best fits my needs after doing hours/days of research.