For me, I will wait for a 4 year gap between #2 and #3. I have 2.5yrs between mine, and when the second was born, I had more problems with the 2.5 year old than the newborn! Now one is 4 and one is 2, and I do love them to bits - it's dealing with 2 year old tantrums and 4 year old attitude and defiance at the same time drives me up the wall LOL So I will wait longer next time, I am lucky in that I have the age luxury, and look forward to having a newborn when the youngest understands a bit more and the eldest wants to get involved - she's put her order in for a sister.

I think it's often something you don't know until you've had them and seen how it's panned out - I wanted them close together at first, as many seem to do, but I do wish I waited a little longer. Not that I would change it for a thing of course