I juggle a demanding professional job, 3 kids, a difficult pregnancy, and that's just the start of it. I try to build in lots of time with my kids, but also avoid letting people down and blowing out arrangements. Sleep is such a wonderful delight when it comes. I REALLY don't want to hear other mums (especially my staff) explaining why they can't make x event / meeting because their child has a cold or whatever.
And another thing, ... love my child-free friends to bits, but have a 3 strikes and you're out rule if they cancel at the last minute due to a crappy excuse - when I've booked the babysitter and jumped through hoops of fire to get out. Am I the only parent of a larger family who gets dead pi**ed off by this?