It's not just a desktop world any more. Now your application may have to run on notebooks, tablets, and smartphones. While mobile targets may not be in the original requirements specification, you'll save yourself time and trouble when you have that software run on, or work with, alternate devices. At the very least, you can avoid erecting brick walls to keep such devices from working. Here’s some design issues you can incorporate now, even if the mobile app is slated for a later iteration.