Sitting on boards where you get compensation Ethics

So just in general, what is the recommended procedures for these scenarios:

Sitting on a board once amonth, get minimial comp

Sitting on a board once a month, get pretty decent comp

Sitting on a board 4 times a month that takes up 20 hours

I’ve been digging through the text but can’t find what Standard this would be germane to , and what the recommended procedures would be.