I lived with an ICU nurse for years and one of the things he emphasized was the risk of acetaminophen overdose. He's more than once treated the liver failure (and death) from it and by his words, it's one of the worse ways to go.

The positive of it is it got me in the habit of logging whenever I take it, either in a note on my phone or just a sheet of paper I place on my dresser under the bottle. This helps make sure I stay under the 3-4g/d limit.

Last year I was diagnosed with a rare headache disease (NDPH). We thought it completely came out of nowhere, but I had logs in my phone recording headaches and acetaminophen use intermittently from a few weeks prior. This proved useful in the diagnosis.

Moral of the story: log when you take it to avoid overdosing. Combine that with some basic symptom logging (like 1 line, 10 words or less). You never know when that might be useful for your doctors later on.