What is the reason radioactive decay is measured in half-life’s instead of just using the elements “full-life”?

Question

Is there something special about the halfway point? Does the decay happen at a steady pace or exponentially?

In: 910

Answer 1

Assume Half-life of 10 years.

A = first 10 years 50% of this substance remains
B = next 10 years 50% of A remains.
C = another 10 years 50% of B remains.
And this goes on forever, since you can never fully decay.

Thus you never can have a full life.