I may not have time to do elaborate crafts at home or be president of the PTA, but my kids don't care about those things, anyway. What matters to them is that I enjoy being with them, that I care to know all about them, and that I love them.
Sure, there are some days when I wonder what I've gotten myself into, worry about the world they'll inherit and consider the environmental footprint of a family like mine. But most of the time, I just celebrate how awesome it is to have six kids.
I don't think there's always a right or wrong answer when contemplating having another child. I do think, however, that there's a certain peace a parent must make with him or herself, regarding this question, or any other.