Can NSUserDefault be overwritten?

Th开发者_StackOverflowere's a NSUserDefault with Value:

[[NSUserDefaults standardUserDefaults] setObject:@"1" forKey:@"aValue"];

Can it be overwritten by the another value? As:

[[NSUserDefaults standardUserDefaults] setObject:@"2" forKey:@"aValue"];

If yes what may be the pros and cons?

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Yes, the value will be overwritten. NSUserDefaults is used to store information even after your app is closed.

This is often desired when you want to (for example in a game) increase the number of levels the user has completed.

The only disadvantage I see is that if you forget the name of a key, you might accidentally write over the value already there when you didn't intend to.