Should Channel 4's Skins take a leaf out of Harry Potter's book?

Maybe the age thing is appearing again, as it seems that the Generation Y cast of Channel 4's popular TV programme Skins, have been told to hit the road and find a new job (much to the upset of my daughter!). The reason? simply that they are too old for the show. The producers have embarked on this risky move (after having built up a large and loyal following) of removing the whole cast and starting recruiting a new cast again from scratch. It is meant to mimic life changes - where you leave college after two years. But TV isn't real life - you only have to look at Harry Potter to see that you can stay at the same school age for 8 years!!!