Well, I have learnt something. Our company tells us to hold each control demand for 3 seconds to "allow the control surfaces to reach full deflection", which has always seemed a bit nebulous to me, since I can see the full deflection on the SD after about 1 second. They did not tell us that the system performs a self check at full deflection and might therefore flag up a fault if one is found.
For what it's worth, I personally watch the Maltese cross move, then look at the SD and confirm verbally 'full left, full right, neutral' etc, checking also that the Maltese cross and the controls are moving in the same direction. This is not SOP, but given that pilots sometimes just say the words without looking, I personally feel this is a check worth doing. NOTE: I don't use the Maltese cross to confirm full deflection, just the direction of control input.
One only has to watch footage of horrendous, preventable crashes where control locks have not been removed before flight, or a full and free control check has obviously not been done, to realise that a control check is a most vital thing to do before every take-off, and should never be rushed or waived.