That's one useful metric, but it's also limited - you're still gambling on an estimated number of uses, which can often vary wildly and in ways you can't predic

That's one useful metric, but it's also limited - you're still gambling on an estimated number of uses, which can often vary wildly and in ways you can't predict. This is further complicated by variables such as companies taking advantage of your assumptions about quality and lifespan of a product by selling out a product line to another company who will produce it at a lower standard for less for the same retail price and hope you won't know or notice. I once bought socks assuming they'd last a long time but the company silently cheapened out on producing them at some point and they were falling apart after just a couple dozen uses. And they were expensive! There's no guarantee that Darn Tough won't do the same, or that you'll spill sauce with turmeric on them and ruin them the first day you get them, or etc etc. At some point trying to explicitly micro-optimize all your purchases down to the socks you wear starts to get lost in the noise and you expend a lot of mental effort on things of minimal benefit, but this is a good thing to vaguely keep in the back of your mind for expensive and/or very frequent expenses that you know you'll always be using.