Before a decision that matters, or a meeting you are dreading, your body often reacts as though the stakes are higher than they are: a faster heartbeat, shallow breathing, a mind already three steps ahead. Grounding beforehand does not change the decision or the meeting, it changes the state you walk in with.
The same sensory grounding approach used across this section, orienting to what you can currently see, hear, and feel, is drawn from trauma-informed clinical guidelines for settling an overwhelmed nervous system. Here it is used to separate your actual judgement from the physical noise of anticipatory stress, so the decision you make is closer to the one you would make on a calmer day.
Two or three minutes beforehand is usually enough. Longer than that and you risk simply rehearsing your nerves instead of settling them. If the hard thing ahead is a conversation rather than a meeting, the three minute reset was written for that.