It's definitely a personal thing and you and only you can know your limit. When I started in birds, nine years ago, it was just Tuchis and then Reggie and then Cooper. I made a decision a long time ago that, for me, I had to realistically stay within the same size bird or I was doomed just because I really needed to be able to let them all out at the same time. That has worked very well for me and one of the reasons I have resisted the Pois I love so dearly. I did have Petey the Patagonian Conure for about four years but due to her allergies to my dusty birds, I absolutely had to find her a new home as her health was in jeopardy. I took in a friend's female D2 and Cooper's sibling Taco and decided to keep Taco because he was Cooper's sibling, but I couldn't do the female D2 and Reggie together and sadly decided that she would have to be rehomed. I wish I would have never made that decision, but at the time, it was what was best for my entire flock. I was also asked to take in a CAG who needed a home when his only other owner was dying of cancer. I almost passed on Clancy but the owner was so insistent that I take him that I couldn't say no. Several years later, I finally decided to take the plunge and get the bird that I had wanted for so long, Kishka, my baby male RB2 who hadn't been clipped and he is my heart and soul.
I was finally at six birds and I truly thought that was my limit. I had moved and I was happy. Tragedy struck and I nearly lost Cooper who was diagnosed with an unremovable mass in his lower abdomen and I did lose Taco, all in the span of a two week period. I was devastated and realized that even though these birds are supposed to live long lives, they can be taken from you in the blink of an eye. I didn't know what to do after Taco's loss and was inconsolable. I didn't know if I wanted another male Ekkie or if I should get a female Ekkie. Cooper missed his brother, that I did know. My vet told me that if I wanted another bird I should go with something hardier like an Amazon or a Senegal. Then I saw videos of Amarillo and my heart was stolen. I went to meet her and she sold herself with her charm and that was that and I was done...until a month later when Chandra told me that she was looking for a home for Abigail because she was worried about the huge size difference between her other birds and Abs. We talked for quite a while and Abs sounded so much like Amarillo and Amarillo didn't have a 'zonnie friend, so I told Chandra I would like to try but that I needed time to absorb the idea of taking on a seventh bird and I still had unpacking to do, so we decided to keep talking and to wait until the new year. In the meantime, another one of Cooper's siblings desperately needed a home and they were going to give this boy to the first person who would take him...I didn't think, I just reacted and went and got him...Ok, we're up to eight birds now if Abs comes home to live but let me tell you, the first time Cooper laid eyes on Wylee, it was like his heart was beating on high again...ok, they hate each other now for the most part but just to see that twinkle in Cooper's eyes again was well worth it and I think they do enjoy each other's company.
Finally, in April, Abigail came home and while Abigail and Amarillo aren't best friends, I think they do like having someone of a similar species around and I don't regret that for a single minute. Sometimes I think, OMG, I have eight birds, but it's a good balance. I have two birds who are really, really needy, Tuchis and Kishka and two birds who are kind of needy, Cooper and Reggie. The rest are really good about entertaining themselves and love a pet or two here or there and are on their way. I think it makes a huge difference that they aren't all attention starved insanity birds.
The decision to make my household a nine bird household with Aspen was kind of a fluke. I had been thinking for a while that I'd really like to get a bird that was Jon's bird. He's a bit sad that none of the greys like him. Clancy is totally hands off for me and him and Tuchis is totally bonded to me. Aspen needed a home and we thought we'd try it. Unfortunately, Aspen seems to be more accepting of me, but is a very skittish bird in general. Once again, I don't regret for one minute bringing him home and giving him a place to land and I'm sure that with time, he will simmer down but I don't know that he will ever be Jon's bird. I'm open to the possibility of bringing in one more grey at some point later in the future, but we'll probably go with a baby that picks Jon at that time.
In the meantime, I'm very happy with my family of nine. We do need to get the basement done (new floor because the carpet is going to drive me completely batty and new ceiling). I don't have kids and don't see them on the horizon if I can help it, so that's not an issue. If we do ever travel, we will have to find a good fid-sitter and that might be an issue but perhaps we can bribe Aunties Deena and Sheryl vacation in Madison. Other than that, things are good. I never envisioned having this many birds...not in a million years. I don't plan on bringing many more into the fold...possibly one more grey and I would never say no to a really sad story of a Rosie in need or a Major Mitchell or a Red Tailed Black Cockatoo but those aren't likely to happen!

My life is the birds...