Tetanus lives in soil, and the booster runs out after ten years

Tetanus is a serious illness caused by Clostridium bacteria. They live in
soil, saliva, dust and manure — everyday places, not exotic ones — and
they enter the body through a deep cut, of the kind you get from standing on a
nail, or through a burn.

The infection causes painful tightening of the muscles, usually all over the
body. It can lock the jaw, making it impossible to open your mouth or
swallow — which is where the old name "lockjaw" comes from, and which is also
why it interferes with breathing and eating at the same time.

Tetanus is a medical emergency and needs hospital treatment.

The part adults forget

A vaccine prevents it, and it is given as part of routine childhood
vaccination. That is where most people's knowledge stops, and it is where the
gap opens:

Ten years is long enough that no reminder arrives and the last one is hard to
place. If you cannot remember when yours was, that itself is the answer.

Before any of that

Immediate and proper wound care can prevent a tetanus infection. Cleaning
a deep wound properly, straight away, is the step that comes before every
other one on this page.

Source: MedlinePlus, U.S. National Library of Medicine.