KiwiSurfer:
As for expired kits, I tried a expired kit once and it didn't have enough of the fluid solution left in the tube so I guess one of the reasons they have expiry dates is because the solution sometimes goes off? Ended up chucking the kit and getting a new one which worked fine straight away with plenty of fluid in the solution.
Last year I did a test and the whole panel bit turned grey, thought that was odd. It had expired some months prior. Bought some new tests and was negative.