For those of you in professions with billable hours (like myself), a time tracking application is very useful. There are countless applications for time tracking on the Mac and iOS. While many are feature-laden products, I use a simple open source application called timeEdition. It’s available on OS X, Windows, and Linux.
Once you add customers, projects, and tasks, using the program is ridiculously simple. There’s a start/stop button for the timer and a separate window to view reports. Minimalist, but very effective. If your primary need is to keep track of your billable hours, timeEdition fits the bill.