A few months back, I wrote about Better Window Manager, a Mac app that helps you juggle your open windows by letting you save their size and positions. I liked the app, but I like Divvy better. Divvy is currently featured as part of $2 Tuesday, which represents a significant discount of its regular $13.99 price for Mac users. There is also a Windows version, and the developer, Mizage, offers free trials of each.
I tried the Mac app and prefer it to Better Window Manager. Divvy makes it quick and easy to resize your open windows. It presents a grid that lets you determine the size and position of an open window with just a click and a swipe.
When Divvy installs on a Mac, it places an icon in the menu bar. Before you can begin using the app, however, you must enable accessibility for it. On Yosemite, open System Preferences > Security & Privacy. Then on the Privacy tab, click the lock to make changes, select Accessibility from the list, and check the box for Divvy. For other flavors of OS X, click here for instructions.
After you have granted Divvy access to your system, click on its icon in the menu bar. A small window will pop up with a six-by-six grid, with the current active application listed at the top. The grid corresponds to your desktop workspace. Click on the grid and highlight a portion of it, and the active app will be resized. Divvy is also smart enough to let you resize multiple windows individually of the same app. For instance, I usually have at least two Chrome windows open throughout the day, and Divvy lets me keep one on the left side of my display and another on the right.
In settings, you can up the number of boxes on the grid -- up to 10 by 10 on my 13-inch, non-Retina MacBook Pro -- for finer control. According to the developer, you can go as high as 20 by 20. You can also set up a keyboard shortcut to call up Divvy, saving you the trip to its menu bar icon.
In addition, you can set up keyboard shortcuts for specific actions. For example, you could create one keyboard shortcut to resize a window so that it fills the left half of the screen and another keyboard shortcut to resize another window to fill the right half of the screen.
Divvy works across OS X's virtual desktops, remembering which apps open in which of your multiple desktops. It also works with multiple monitors, according to the developer, but I did not test this functionality. On my old MacBook Pro, however, Divvy saves me time in arranging my open windows for maximum productivity.