Is it necessary to always use [unowned self] in closures in Swift?

Hi everyone! I'm a beginner iOS developer and I'm having trouble understanding retain cycles in closures. Here's a simple example: I'm making a network request inside a controller. ```swift class ProfileViewController: UIViewController { var nameLabel: UILabel! override func viewDidLoad() { super.viewDidLoad() fetchUserProfile() } func fetchUserProfile() { APIClient.shared.getUserProfile { [weak self] profile in self?.nameLabel.text = profile.name } } } ``` I see that many people use `[weak self]`, but some write `[unowned self]`. What's the difference? When should I use `unowned`? Or is it better to always use `weak`? I've heard that `unowned` can cause a crash if the object is