It's a U-shaped mortality curve. More generally, many things show a Pareto power law distribution: if the thing has existed for 10 seconds, expected remaining l

It's a U-shaped mortality curve. More generally, many things show a Pareto power law distribution: if the thing has existed for 10 seconds, expected remaining life is 10 seconds. If it has existed for 2 days, expected remaining life is 2 days. And so on. It shows up in a lot of places.