Since Xcode 7 was released, a target device has now free provisioning. A developer doesn't have to sign up for Apple Developer Program in order to test his/her app on an iOS device.
When you uploaded your application on an iPad or iPhone, you'll also have to trust the developer. So, on a device go to Settings
>> General
>> Profile
>> Developer Account Name
>> Trust
.
The problem is an app with free provisioning works on your device only 7 days.
Is there a way to make it work perpetually on iPad (without building an app in Xcode again)?