I have two kids, daughter 4, son 3, and life is very busy and never any rest. Daycare is expensive but we are getting to the end of that so we are about to see the light at the end of the tunnel. However, my wife and I have had discussions about a 3rd child (she said she has always wanted 3) and I love the idea of another as I love being a dad, but the stress that comes with it, and now that we are so close to gettin done with diapers and day care, I dont think I would want to go back through all that again.
I cant imagine 4 kids at once, a parent would have to stay at home unless they have a relative who is willing to watch during the day