What is the best approach of making a timed demo? My app has gotten much better and version I send out to friends and testers I want to. I am guessing when they open the app for the first time it records the date and I save that information using the NSUserDefaults and check the date when it launches? If the date exceeds the demo time it quits out the program. But if they keep downloading, or duplicating the app they get another 7 days if it is embedded in the app. So storing some file on the computer would also be needed? What is the best approach?