I went from 1 DC to 3 DC, courtesy of having twins second time round and the first couple of years was pretty hellish!! But then, DD1 was ill for most of the first year (suffering symptoms of undiagnosed coeliac), we moved house and the DTs were terrible sleepers.
Now it's great...they get on well (most of the time) and have similar interests. The next few years will be fun, when they're all hormonal (and I'm likely to be menopausal too), but hopefully we'll emerge intact and sane 
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However, holidays are expensive - in fact doing anything as a family is expensive, as the 'family' tickets are always for 4. We had to get a new car (and then another one a year later because, in our twin-baby fog, we didn't measure up properly for stage 2 carseats). And our food bills are huge and only getting bigger - all three are coeliac so that has something to do with it, but it doesn't account for the amount of fruit, veg and biscuits we get through!!
To be honest, I doubt I'd have had three, if fate hadn't intervened, but I can't imagine life any other way now 
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