After 100 then they charge us a fee for every 10 GB over that.
I’m not really worried about it. But my wife panics about stuff like this. It becomes an obsession and she’s now checking all the nests, echos, key locks, etc…and she is pretty convinced someone is stealing our data.
So even if we just say okay upgrade to unlimited, which is what I would to, she will never not believe that something nefarious is going on.