I have read several articles discussing pros an cons about singleton patterns. But I would like to know:

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> Is it advisable to have multiple singletons in an iOS App?
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> 
> 

what are the pros and cons...?

Currently I am having only one singleton globally and holding strong references of other necessary properties including custom composite classes. But the idea sounds something strange for me for an example, accidentally I can create several instance of a custom composite class which I don't want.