Hi there we actually have the same tickets and we used the last park day in 2009 and still have a water park day left! When we were there in 2009 we went to the ticket booth and were told just to go to the gate and they went through as normal ! A very senior gentleman who was on our gate advised us that even when we have used all our days we should hold on to our used tickets as these are millenium tickets and as such are collectable ! Hope this helps. Don't know about universal do they not expire? Pauline