I have to work on an IPhone application similar to IPhone app store [device]. As u all have seen it is a tabBarController application with a collection of navigationcontrollers with each nav bar having their viewcontrollers/table view controller. My question is related to memory issue. As I am getting data from a web service and populating them in various tab bar's view controllers/table view controllers I will be working on this kind of app for first time. The no. of tabs will be 4. Does it may cause any substantial memory leak problem? I am asking this because i have to fill viewControllers property with collection of nagiation controllers. Can it be possible that in a tab bar application v can populate data only when needed?