File early. The window is shorter than people think and it starts at the transaction.

Three questions kill most of the confidence in a thread like this: sample size, blinding, who paid.

The pain score conversation is thirty seconds of my life I will never get back, every time.

Same.

Photograph everything before you open it. Ten seconds, settles most disputes.

Bring a list. Embarrassment makes everyone forget things, including you.

Test one thing at a time. It feels slower and it is the only way to learn anything.