>People are really likely to rebuy things. I’m not really sure why

Time consuming research (starting with filtering out advertising budget powered fake reviews) and short-lived products & brands make personal experience & recommendations a lot more useful. If someone around me has an even remotely similar set of requirements and budget for a product, they are much more likely better off trusting my recommendation and (having me) order another one right away. It used to be less clustered around one person or calendar date, when brands stayed around and kept true to their previous performance for longer. Nowadays I even order duplicates for myself, not because I really need 3 of them in the near-term future, but because I am worried that I will want a replacement in a year and another one the year after.. and I won't find exactly the same then.