This tip is short and sweet: If you have two calendars, make sure they are synchronized! With the new smartphones out there, computer and handheld devices can easily be synchronized so you don't miss any appointments or opportunities.
The best thing to do of course, is to use one calender but with teens, games, music lessons, gymnastics, husbands, dinners, work (whether working in the office or working at home), a household calendar and a separate smartphone calendar is probably the norm.
No worries. It can work if everything is synchronized!