When we should NOT use neither [weak self] nor [unowned self]?

I've read several discussion on StackOverflow about when we should use [weak self] or [unowned self] in closures.

However, are there any cases when we don't have to use neither of them since Swift doesn't show any error or warning when we're just explicitly using self inside a closure.

For example, should we use weak or unowned here?

UIView.animate(withDuration: 0.3) {
    self.view.alpha = 0.0
}