From Alex Laird:
Time Keeper eliminates the hassle of remembering when you signed in and signed out, because it remembers for you. When your computer starts, just sign in, and get to work. Time Keeper takes care of the rest. Throughout the day, transition easily between charge numbers without ever worrying about losing track of hours. At the end of the day, simply stop Time Keeper and head home knowing that your hours have been safely and accurately stored. Time Keeper also maintains a comprehensive history regarding your hours. These personalized records are exported to a spreadsheet on a periodic basis-monthly by default, but this can be customized. This makes it easy to look up past details from hours worked to the charge number or specific tasks.