set an attribute with or without check

set an attribute with or without check

I've learnt that's better first to check if an attribute is already as I
like and only then to set it again. If I'm wrong, just say it!
Short example: If I want to clear an JTextField (set text to ""), should I
check the existing value first and if it's not yet correct, set a blank
string.
...
if (jtextfield.getText().equals("")) {
jtextfield.setText("");
}
...
Or should I set the text directly without checking first?
...
jtextfield.setText("");
...
Which of these versions is better? Which do you prefer?