Parental Strategy for Lateness and Time Management Problems

Time management and lateness seem to be related as you're describing it to anxiety in some way. What is a good parental strategy for chronic lateness and time management problems? If your kid consistently takes 20 minutes to leave the house and you consistently only give them 15 minutes, that's on you. Also use your calendar and depending on the age of the kid, they should be using calendars too.