[user104658]

It's a strange multiplier to be honest. One is hard, two is 100x harder than one, but then 3 and even 4 aren't that much harder than 2 (based on what friends with more than two say).

Basically one is life changing but you can give one kid your full attention, adding "more than one" into the mix divides your attention and is immediately a different ballgame, but once you have more than one, it is what it is.

I think at 5+ things start to get a bit silly though unless there are large age gaps. You can't possibly be giving each child the attention it needs. If there are big age gaps then each to their own, I guess... If you have two kids who are off to Uni and another two who are in primary school, it's not really any different to just having two in practical terms, is it. Just that you're doing it for a second time.