For personal use, apps can be installed on all the devices a customer owns. On the App Store in iTunes, apps will be tied to the iTunes account from which the purchase was originally made. If you own multiple devices, for example, an iPad, iPhone and iPod touch, you can sync all the devices to a computer with the app and use it on your iPad, iPhone and iPod touch.
If the app is on a device used by multiple users (such as at a school or assessment centre), one license per device is required for each app.
Please note that Predictable for iOS and Predictable for Android are separate pieces of software requiring separate licenses, whether for personal or for professional use.