In classes that implement INotifyPropertyChanged I often see this pattern :

    public string FirstName
    {
        get { return _customer.FirstName; }
        set
        {
            if (value == _customer.FirstName)
                return;

            _customer.FirstName = value;

            base.OnPropertyChanged("FirstName");
        }
    }

Precisely the lines

            if (value == _customer.FirstName)
                return;

are bothering me. I've often did this but I am not that sure it's needed nor good. After all if a caller assigns the very same value I don't want to reassign the field and, especially, notify my subscribers that the property has changed when, semantically it didn't.

Except saving some CPU/RAM/etc by freeing the UI from updating something that will probably look the same on the screen/whatever_medium what do we obtain?

Could some people force a refresh by reassigning the same value on a property (NOT THAT THIS WOULD BE A GOOD PRACTICE HOWEVER)?

1. Should we do it or shouldn't we?

2. Why?