We are currently looking after our GC (aged 5 and 7) while their parents have a couple of nights away.
We can cope during the daytime, they are boisterous, lively children with lots of energy, but we have lots of activities planned and have had a lovely couple of days.
The problems come at bedtime. Their normal routine is that they have dinner at 4pm and start getting ready for bed at 5pm. This involves both of them reading and their mum and/or dad reading them a story. However long and drawn out this is, though, it always ends with them fighting and laughing at each other, running in and out of each others bedrooms, hiding, saying the want a drink, need the toilet etc etc. After much shouting and cajoling, one parent usually stands guard on the landing while the rest of the household has to remain in absolute silence for 30-40 mins while they go to sleep. The whole rigmarole takes one and a half to two hours.
While we have been looking after them, we have allowed them to stay up til 6pm (which is still pretty early), and shortened the bedtime routine to one bedtime story. (Having explained to them that we are letting them stay up later on the understanding that they behave at bedtime). Obviously though, they still continue the running around, laughing, fighting etc. No amount of reasoning, threats, promises work, they just laugh in our faces. We are exhausted.
I'm thinking of telling my DS and DDil that unless they get this sorted we cannot look after them again, which would be a shame as we do love the daytimes with them.