How do you know when you're "done"?

DH and I don't have any bio kids. Shortly before STBAS came into care, we had actually decided not to have kids. I have some health problems which means that a) it will be really hard on me to try to get pregnant b) it will be really hard to get pregnant c) it will be really hard on me to be pregnant d) it will be really hard to stay pregnant (and yes, those are all distinctly different items!) At the time DH was opposed to adoption, didn't even want to discuss it. So we figured we wouldn't have kids. We were okay with that decision. When we took STBAS, we talked at length about it and decided we were in it for the long haul and if it did come to adoption we would do it. Of course, at the time we figured there was no way it really would come to that ... but as of next Thursday, it will! ;) the thing is, it's tough sometimes for him to be an only child. Technically we live in a subdivision, but the "lots" are several acres and it's not a neighborhood where you can walk down three houses and play with the neighbor kids. So we're pretty isolated and we'll have to make playdates to get him company around his own age. Also, in some ways it would be nice to have two. And ... selfishly, I really want a girl!! I know that if we had bio kids there would be no guarantee on sex, so that aspect seems kind of "wrong" to want to pick the sex. But the same health problems that are stopping us from trying to have bio kids also make it rough on me sometimes to function. (You know how you get a horrible stomach virus, spend 24 hours puking, and then once you're over that you just feel achey and weak and don't really want to move from the couch? That's how I feel almost every day. I also work full-time. It sucks.) I know that most kids are not like STBAS -- he is not just a handful, he is like five handfuls -- and another kid doesn't necessarily mean it would drive me over the edge. But the thought of TWO of him makes me want to lie down and cry. We've talked a little about it and would want a girl somewhere in the range of 4-9. We are not willing to foster (we think it would be too hard on STBAS) so she would have to be legally free. I don't even know if legally free single girls in that age range are ever available in our area. I have asked workers about it but they always just say vaguely that "oh, it always varies". So possibly after all this debate we might not even end up with a kid. We have a 6-month wait after finalizing the adoption, but we'll have to decide I think in November if we want to renew our license. So it's something we'll be chewing over for the next several months. I am just wondering, though, how do you know when you can't handle any more? Do you know you have a limit? I don't know if one is my limit. I just think if I struggle with one then how could I possibly handle two? But he is getting older and more mature and I have a feeling in the next year or so will start becoming a lot more independent. If you have health problems too is that a consideration? I don't remember who but I seem to remember someone here mentioning having MS and someone else having lupus. I have seen people on here say they are done ... but then they end up not being done after all. (You know who you are, haha.) (I also feel kind of pathetic agonizing about adding a second kid when there are people here who are debating adding a fifth or sixth!) I know it's something we'll have to talk out and figure out on our own, I am just curious what other people go through trying to decide the "done" point.