Give the user a choice to include or exclude an item on monthly caledar.
The amount of space on the monthly calendar has to be limited, so I use mine to obtain a bird's eye view of major events in my month -- days when I will be traveling or having guests, important due dates, and holidays. I use my daily calendar, where space is less limited, for major and also minor events -- such as lunch. I have no need to see "lunch" and such items on my monthly calendar, and they only make the month view seem cluttered. Along the same line, I don't really need to see most to dos on my monthly calendar. It would be great if I could choose whether or not to include such items in the monthly view.