Grindstone may be just the application you need, if you want to keep track of how you spend your time. We have used it for years.
The application allows us to track time by client and/or project and activity in real time. If you forgot to track something, you also have the opportunity to manually add time later. You can even issue invoices.
Once you set up your preferences, the free version has many useful features:
A display reminds you that you are timing something. Should your activities be perceived as “not active”, upon your return to the computer you’ll be asked how to treat this inactive time. There are also pop-up reminders that you have spent a considerable amount of time working on a particular task (should you get up and move around a bit?). Other pop-ups will remind you of what you are currently tracking.
We have found the free version of this application suitable for our needs, as well as reliable. For teams, synchronization across devices and more, there is also a paid version.
Learn more about Grindstone here: www.epiforge.com/Grindstone