I let mine out nearly every day. We have sheer curtain in front of the windows, so they don't think to fly into them since there is not a clear view of the outside. At a previous apartment they did fly into the windows all the time, so I kept their wings trimmed so they could just barely fly, but could not fly fast enough to cause injury. I think it took them a couple months to realize they should aim for the window sill, not the window. It was rather amusing to watch after I addressed the flight speed issue and felt sure they were not going to hurt themselves.
My boy parakeet does indeed like to make super close passes when he is flying around and you are sitting still in the room. I think he does this to show off for the girl. I've gotten used to this behavior he has so it doesn't bother me. I just remain still when I sense him coming so I don't bump into him. My poor girl bird can hardly fly at all because her wing feathers don't fold correctly on one side. When I got her I thought they had just been clipped too short, but once she grew new ones I realized she seems to have a defect of some kind and they just don't grow right. She hates to come out of the cage because of that and I have to coax her to even try to fly. I think she is embarrassed that she can't fly like he does.
