I try to find as many forums as I can for people who are more likely to know about the product, like enthusiast forums for things like headphones, and professional forums for things like washing machines. I try to get a feel for what parts of a product fail most often, then try to find products where people have specifically reported those things holding strong. There’s probably more I could do, but even just that has led me to finding products that have lasted far longer than buying the cheap stuff on amazon had gotten me.