Sometimes an app comes along that's so deceptively simple yet incredibly useful that you wonder why someone didn't think of it sooner. Caffeine is a free app that stops your MacBook's screen from dimming--regardless of the current settings in the system preferences--so that you can watch YouTube videos or your favorite Family Guy episode without worrying about waking up the screen every few minutes.
After you've downloaded and launched Caffeine, the app displays a little coffee cup in the menu bar at the top of the screen. Clicking on the icon changes it from an empty cup to one brimming with piping hot java and launches the app. Right-clicking on the cup opens a drop-down menu where you can select how long the app will keep the screen lit. Options range from five minutes to five hours to indefinitely.
We initially set Caffeine to keep the screen on for five minutes. After that time passed, the screen automatically dimmed in accordance with our energy saver preferences.
The preferences menu also gives you the option of starting Caffeine when you start your computer. We recommend doing so because the usefulness of the app is dependent on being able to easily access it. It would be nice if the default setting for the app loaded it at startup instead of the other way around.
Overall, Caffeine works exactly as promised. It's an easy way to disable or enable screen dimming without having to dig through the energy saver menu each time you watch a video or do anything else that requires maximum brightness.