system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is the reason radioactive decay is measured in half-life’s instead of just using the elements “full-life”?

Is there something special about the halfway point? Does the decay happen at a steady pace or exponentially?
gpt
The half-life isn't the half-way point. That is, if something has a half-life of 5 years, that doesn't mean it all decays in 10 years, it means that it takes 5 years for half the substance to decay. In the next 5 years half the remaining substance will decay, and so forth.