How Many COVID Tests Are Enough?

Yesterday I came down with a scratchy throat so I did what many of us have to do these days.

I bought a bunch of COVID tests.

First one yesterday night was negative.

Hmmm, but maybe it was because my symptoms had just started.

Next one this morning. Also negative.

Hmm, maybe I didn't stick the swab far enough up my nose.

I should probably take another one.

And then another.

Are ten enough?

Will I be sure then?