We did it. Result: joy, unexpected involvement and helpfulness of older siblings (then 6 & 7), mess, untidy house, more shouting in the morning getting ready for school, lots more washes and a lot less ironing, more hilarious and scary moments, a squashed working day, less time for TV, more joy, more shouting, more chaos, more lateness at school, more late pickups from school, more picnics, more eating grass and picking flowers, very little time for PTA or other volunteer stuff. Was it the right thing to do - yes from our point of view. Would I now want a 4th? Post-40, NO, definitely not.