I have had these two parakeets for about 6 or 7 years. I've never had any problems with them and I've never taken them to a vet.
Usually we leave our cage open every day so then can get out and fly around a little. They're smart, so they know how to get back into the cage and where it is.
But today one of them came out of the cage and tried to fly but fell on the floor. I'm sure she wasn't really injured since it was a really small drop, but she just had trouble flying and still does right now.