See the differing personalities played a role in our initial decision. Our first son was (and still is) very placid, compared to our second he was so easy to look after as a baby. He rarely cried, and was just very low maintenance. Our second was a shock to the system! Cried for months due to various health issues, crying is really stressful when its not something you're used to. I thought tandem breastfeeding would be a great way for them to integrate and for my toddler (then 2) to feel included. It was so difficult and i had to stop after 7 months, again more reasons than just the logistics of tandem feeding.
As i started to see Ds2's personality emerge it was clear they were like night and day! Ds1 would only ever sleep with us, so we co-slept for 2 years. He was a pleasure to BF, whereas DS2 wasn't, again, health issues for both of us and no support made for a difficult BF experience. Weaned at 7 months and he was so much better on formula, whereas DS1 was BF for 2 years & 8 months. DS2 is so active, we've had to childproof so much stuff we didn't have to with DS1.... things he would never have touched my second is right in to. It's weird! Also DS2 would never co-sleep! he would muck around until we put him in the cot and then go right to sleep. I bonded with my first via BF & co-sleeping, I've had to see that i can bond in other ways with my second with whom we needed to do things differently.

So it was going by DS1 personalit that we thought all babies were like that, so we thought having 2 wouldn't be too difficult but it really has been. I had no idea that i could have another baby and it be so different from my first!