I have always had the mindset of, "play with the hand you're dealt" to the point that I have not mulliganed, ever. That has recently changed thanks to playing a different card game and coming to understand that the ability to mulligan is not only a part of the game, but an integral part which can mean the difference of setting up your team on site 1 versus site 3.
I would like to hear some strategies you use to trigger in your mind the thought of, "I need to mulligan this hand."