i think u need to feel very comfortable with who ever u are leaving ur children with.
We left DD & DS when they were 3 & 1 1/2 for a week just this last august gone with my in laws. They had a ball & DF & i had some well deserved time out.
We are actually leaving them again this saturday for another week with the in laws. Both dd & ds are super excited. They both have their own bedrooms & toys when they go for stays with them.
Next feb we are thinking about going os for 10 days - 2 weeks. This i think i would be alot harder.

My kids have had alot of overnight stays since they were quite small, with my mum & in laws. So i guess we feel comfortable leaving them for longer periods of time.
Thats just us tho. Like i said at the begining, u really have to feel comfortable doing it & with who they are with otherwise u just wont be able to enjoy urself.