I have 3 kids....trying for #4 so obviously it is not all that bad. I will say we ttc#2 when #1 was only 8mo. DD#2 was a tough baby & I was in no hurry to have #3. Colic nearly killed me so going 1 to 2 was very hard. We were not trying when we got pg w/ #3 (DD#2 was 20mo old) & I was worried. After #3 the first month or 2 was not bad but then it got really hard for me...but I had underlying medical issues that were not treated at the time. About when I finally got on meds (when #3 was 1yr old) things turned around a lot. I've really enjoyed having 3 for the past 2yrs especially. She was not colicky & is such a wonderful piece of our family. We still did not start ttc#4 until she was 26mo. Now she's almost 3 & we are still trying....I came from a large family (5 kids) & really enjoyed it by & large and would love more kids (though I am nearing 37 & generally am not super fertile)...so we'll see.
For me personally, going from 2-3 was much, much harder than going from 1-2. My boys are 7 and 5 now, and my daughter is almost 20 months old. I feel like my life is always in complete chaos mode. For me to even "nest" (or "GBCN") this evening is something out of the norm (nice break though). DH has been in the living room with the kids playing and the weather has been crappy. I'm in the midst of making dinner and so far something that would take me 10 minutes or less (checking out this board) has spanned over 2 hours because there is always interruptions. I feel like I can't think a complete thought or read something without an interruption. It would be really nice to have no interruptions (and sorry if this sounds choppy, I've been interrupted 5 times now!) I have become the mom I said I would never become: The one who is disheveled and seems to have a serious case of A.D.D. This only came about after my 3rd stopped sleeping 22 hours a day! I remember, after I had her, thinking "This is no problem at all." Then a few months later, thinking "What crack was I smoking thinking this is no problem!?"
Don't get me wrong though - I love the chaos. I wouldn't trade this for anything! But it is a chaos. And definitely more expensive.
We have 3 girls, 9, 4 and 2 and I'm not going to lie it was a lot harder for me to go from 2 to 3 than 1 to 2. I think it was just because I was trying to do too much and DH was working a lot when I had DD3 that it was just overwhelming but its much better now. I love having 3 girls, DH wants another but I think I'm done.
We didn't change much, we still have sedans that fit 3 car seats, well my oldest is out of a car seat so shes in the middle. My 2 oldest share a room, we live a modest life style so having 3 hasn't really added a huge expense for us. It will later on when they get older I am sure of it.
I only have 1 brother and DH was an only child so we wanted a bigger family
We had our 3rd almost 6 months ago and it was one of the best decisions we've ever made. Keep in mind that he is the sweetest, happiest baby ever & I am madly in love with him, so take my input fwiw.
Our lives were already pretty child-centric, so transitioning to 3 didn't seem like a huge deal. I'm a SAHM, already drive a mini-van, have a big enough house and a great support system.
It has been by far the easiest transition. The only 'challenge' that I've faced at all is forgetting how long it takes to get out of the house with a baby. Other than dealing with diapers, bottles & diaper bags again it's been pretty smooth.