i think besides the initial baby years, its easier to have more than one, as they can play together (and i suppose fight together too unfortunately).... i often look at our 2.5 year old and think 'oh she needs a playmate sibling NOW'.... she'll have to wait a while until this next baby is big enough to be a playmate, but i definitely feel if there is more than one they can occupy each other, rather than always having to interact with an adult for entertainment....
i'm sorry but i think four kids would be a lot of work!!!!!!!!!!!!!! when they are older it would get easier, but there would be a lot of car trips to all their activities etc....
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