I'm a college student using this application for everything from assignments to tasks for clubs I'm in. It can be very confusing to have to go back and forth between this application and my calendar to see when something is due. I often get assignemtns on a tuesday that aren't due for a week, but i still need to have them in the app or ill forget. Best way to automate this would be to prompt users when entering the task to give a date for when something is due. Then the colors are associate based on the due date. for me being in college, and nothing is ever really due past a week, red would be one day, yellow being 2, and green anything past 3. That way I can look at my schedule and make sure to address all the red items before even thinking about yellows and greens. To fit this to your tasks, there should be settings for every color, maybe some people want red to indicate everything due within 3 days, yellow for 5, green in a week, etc.