Is it necessary to use a weak reference to self inside closures?

Using a weak reference (weak self) inside closures in iOS is not always necessary, but it is often required to prevent strong reference cycles (retain cycles).

If a closure captures self strongly (a strong reference), and self holds a reference to that closure (for example, through a property), a retain cycle occurs, and the objects will not be released.

An example of correct usage of a weak reference:

someAsyncOperation { [weak self] in
    guard let self = self else { return }
    self.doSomething()
}

If the closure is not stored in a property of self and does not create cycles, then using a strong reference is fine.

In summary: use weak self when the closure might hold onto self and create a retain cycle. In other cases, it is not necessary.