3 is hard, and not just the age! My best friend sent me this news article: "Mom Survey Says: 3 is Most Stressful Number of Kids". Some moments, I totally agree.
After giving birth to Jackson, we knew we wanted baby #3 some day. My midwife then advised me that if you have 3 kids, you might as well have 10, because 3 was the tipping point.
Thankfully, most of the day, it doesn't feel that hard. It was much harder when there were 3 of them aged 4 and younger. But even now that they are older, there are moments that it seems a bit unruly. I vaguely remember that there were moments that 2 felt hard, or that 1 felt hard too.
The interesting point of having more kids is that when you have 1, you think, "oh goodness, I can barely get out of the house with this child". Then, when you have 2 kids, and you only have 1 kid with you, you think "whew, this is so much easier than having the 2." Then when you have 3 kids, and you only have 2 with you, you think "whew, this is so much easier than having all 3". It is all relative.
We thought at the beginning that 3 would be the right number for us, and it seems just right.