What many want to do, however, based on perhaps old habits of writing daily to-do lists, is put actions on the calendar that they think they’d really like to get done next Monday, say, but that actually might not, and that might then have to be moved to following days. Resist this impulse. You need to trust your calendar as sacred territory, reflecting the exact hard edges of your day’s commitments, which should be noticeable at a glance while you’re on the run.