Question

Just curious is it mandatory. For example in my app, I just push and get info from [NSUserDefaults standardUserDefaults] without any need of “synchronize” call. Maybe I’m missing something but I haven’t noticed any problems (YET) :). I know that this call should make synchronization between in memory and on disk data but why it is unnoticeable in my case?

Answer 1

synchronize

Because this method is automatically invoked at periodic intervals,
use this method only if you cannot wait for the automatic
synchronization (for example, if your application is about to exit) or
if you want to update the user defaults to what is on disk even though
you have not made any changes.

It’s not mandatory, but if you update data and your app gets killed right after, you will lose information.