I buy products based on my own past experiences and based on reviews. When a product is favorably reviewed by multiple reviewers, it’s a component worth considering. I also consider products from manufacturers whose “house sound” I enjoy.
I avoid products posters with hearing deficiencies own. If somebody tells me they cannot hear the difference in cables/capacitors/fuses, whatever he owns is worth avoiding.
Ditto for equipment owned by those who seem a little “off”. Those with overinflated egos and exaggerated self worths tend to promote products based solely based on the fact that they own them, no matter how flawed the sound. Worth avoiding.