I have zero business thinking about having a third child at this point in my life, but you wouldn't believe how soon people started asking me if we were done or not. (Let's put it this way: I hadn't left the hospital yet.)
It's easy to be all, ha, ha, whatever about it, but I came to the startling realization that the jump from one kid to two kids is VASTLY different from the jump from two to three, at least in terms of finances.
Our three-bedroom could technically house more kids without complaining too much, but not for long, I don't think. The bedrooms are small and not conducive for sharing between more than two kids, and I don't like the idea of being on a different floor from tiny children. Also: one bathroom. (Okay, 1.5 - still one bathtub/shower.) As it is, the four of us sleep in four different rooms in order to maximize the amount of sleep everyone is getting, and I don't know how that would work with a fifth person. Who'd be sleeping in the kitchen?
Non-negotiable, we'd need to buy a larger car. Ours can fit two car seats safely but not three, and not two car seats and a person in the backseat. And Peanut's Jeep - well, there will be no kids riding in that thing until they're old enough to drive it. Minivan city. (Plus higher gas prices...would insurance be lower or higher on a mom-mobile?)
Replacing instead of reusing
Baby Bear is currently using Pickle's old bucket seat, but this hypothetical third child might need his or her own new car seats due to the expiration dates on the plastic parts. I have bought three car seats already; it pains me to think of buying more. (We have a portable infant seat and two convertibles - because we already know that Pickle will still be small enough to need one by the time Baby Bear outgrows the bucket.)
When updating our beneficiaries, I thought about whether we needed to up our life insurance policies as well, but figured that they are generous enough to be split between two kids in the unlikely event that something happened to both Peanut and I. (Pickle may disagree if it ever occurs to her that she would have been the sole recipient until just a few weeks ago....). But add a third kid to the mix and we'd definitely need to rethink that.
College tuition, weddings, etc.
I can't even bear to think of it.
While we wouldn't make the decision to have another child based on finances alone, the question "can we afford it?" would have to be very carefully looked at. I don't think it's something we even thought about when we decided to have a second.