For us, we decided when the backseat of the car was full, that was enough. We had three. We do not regret that decision for one moment. Think of everything, do you want to get a three to five-bedroom house? Do NEED to have a minivan or SUV to seat your family? How about the cost to feed three or five teenagers (YIKES)? Clothing, schools, extra activities... Plus, now that my kids are older, I spend a lot of time running my three kids, to four different schools. I couldn't imagine adding another to the mix. If you're in doubt, don't take the plunge. We knew before baby three was born that she would be the last.