>saying Pareto distributions follow linear relationships No; not sure where you got that from. >For a product at T = 0, why would it be optimal to assume its

>saying Pareto distributions follow linear relationships No; not sure where you got that from. >For a product at T = 0, why would it be optimal to assume its lifespan would be T = 0 as well, rather than the average age of all products? I'm not saying it would be. (The original blog might, but that's irrelevant to my posts here.) If you knew the average lifespan of all products, that would be your best estimate of the lifespan of a new product. (You can't use average age naively without thinking about right censoring.) If the average lifespan of a product was short, then the average lifespan of a new product would be short. As the product aged, it's expected lifespan would increase. I.e. the longer something has been around the longer it will be around, or, equivalently, the shorter it has been around the shorter it will be around (both obviously taking about expected times.) Make sense now?