I say go with two if the birds like being together. I have two brother white winged parakeets. They are over two years old and I have had them for over a year. They are together all the time, they preen each other and eat together but they argue too. One is more friendly, the other more scared, but they both want to be with me, and at the same time. They are happy together when I am not there. I would feel awful if they were alone and would rather have two birds bonded and ignoring me rather than one bird alone a good part of the day while I am at work. You will/can have more interaction with the bird that isn't scared. They learn from each other, and the scared will learn trust watching you with the friendly one. I work with both of mine at the same time and they are patient but I have to approach the friendly one first or the scared one gets too nervous. Actually, now that I think of it, most time I see or read about two birds together, one is more human oriented than the other. Good luck.