Do you feel hurried all the time? It may be that you become so involved in what you’re doing that you don’t glance at the clock often enough to keep yourself on track.
Also, you may not account for the time you need to go from one activity to the next. I don’t mean accounting for driving time but for the in-between, or segue, actions, such as pulling on your coat and collecting your keys and purse that eat up the few minute difference between feeling you’re on schedule and being on the edge of running late.
Try setting a timer to go off 15-minutes before you need to head out the door so you can wrap up what you were doing and transition to your next task.