Obviously adding more children means more work and less time, but IME 2-3 was the easiest. 0-1 was the hardest because you have no idea what you're in for.
It really depends on how close together the kids are. I know someone who had 3 kids close together (like all 16-17mos apart) and it was very difficult. When we had DD her brothers were 5.5 and almost 3.5 and the oldest had just started kindergarten. Super easy.
0-1 was much easier than I had anticipated. 1-2 threw me into a complete tizzy. It was really difficult for me, but I think my PPD had much to do with that. 2-3 was a really easy transition for the whole family. I kept waiting for the other shoe to drop, but it never did. I think so much depends on your mental state, the age spacing of your children and their general temperaments.
I have no help bc I only have one, but this reminded me of a Jim Gaffigan quote: "what's it like having five kids? Imagine you're drowning, and someone hands you a baby." Lol.
0-1 was a million times harder than 1-2, except for not being able to sleep when the baby sleeps this time. Hoping 2-3 ( if we go that way) is the same.
1-2 has been tougher than I expected, but not harder than 0-1. For me, it's hard to compare between these two transitions. 0-1 was hard because we had no experience and my baby had reflux. Once we got him sleeping well, however, life pretty much resumed as before but obviously our lives were more planned and scheduled. We have 2 now - 3.5 yo and 5 month old. It is hard because we are dealing with 3.5 yo's normal but frustrating behaviors while also taking care of the baby. But I'm not sure if it would have been easier dealing with DS's antics and attention demands even without the baby. I would have been just as frustrated - just a bit less stressed out I guess.
I only have two kids, but I found it to be infinitely easier transitioning from 0 to 1 than 1 to 2. DD1 was almost 3 when we had DD2, but it was awful not being able to spend much time with her or focus on her like I did before DD2 came along. I had a c/s so that didn't help either, but just the exhaustion of having a newborn really took it's toll. It's better now that DD2 mostly STTN and is old enough to play with DD1 some, but I still reminisce about how much easier when we only had one kid. Not that I would give DD2 back if I could. It was just a really difficult transition.
Re: PR - The Transition
1-2 I've done this before. Wait. I still have to take care of this other kid and a baby? Hold up. I need a breather. Ok, I know what I'm doing.
2-3 Anyone bleeding or is something on fire? They're fed and don't smell too bad. I'm good.
I know someone who had 3 kids close together (like all 16-17mos apart) and it was very difficult.
When we had DD her brothers were 5.5 and almost 3.5 and the oldest had just started kindergarten. Super easy.