Hazard Rate

In economics, the Hazard Rate is the rate of death for an object or entity at a given age.

So a person's statistical likelihood of dying will generally drop following infancy (there are quite a few things that can go wrong right after birth across much of the world), but it will then tick back up over the course of their lives as they engage in riskier behaviors, the biological effects of aging accrue in their bodies, and as they ultimately approach humanity's (current) lifespan ceiling.

This formula can also be applied to goods, like smartphones, which might be unlikely to die in their first year of operation, but then see an increase in hazard rate as it becomes statistically more likely that a phone's owner will drop it, causing severe damage, or that the device's hardware or software will suffer some kind of irreparable glitch.