We only have one grandson, 8, and he is a proper Duracell bunny! Children that age don't understand the concept of ageing. We are a fit 68 and 73 respectively, but this past year we have begun to find it increasingly hard to keep up with him. We have him for two overnights during school holidays (which compared with some on GN, doesn't sound a lot - we only have one to look after!) and by the time he has gone home we are on our knees. And yes, as has been said, you do worry constantly about them hurting themselves on your watch.. I am far more risk-averse with him than I was with my own children. But when he's gone home, we miss him tremendously, and realise that there will come a time - and who knows how long away it will be - when he won't want to hang out with a couple of deaf, shortsighted old coffin dodgers who can't kick a football! So it's business as usual till someone calls time!