LO is 7months old. He's been sitting unsupported since he was 5.5 months old. Last night he decided to show us a new trick, going from being on his stomach to sitting upright all by himself. He'd shown almost no inclination of doing that less than a week ago. In fact getting him to stay on his stomach long enough for him to do anything interesting w/o complaining was always a task. Last night he just kept moving from sitting to stomach to sitting again, over and over.
This morning I placed LO in his crib on his back so I could get dressed, found him sitting upright in it a few minutes later. Time to lower the crib before he figures out how to pull up!
ETA: Daycare reported that he stood up in his crib yesterday, so the crib at home was lowered last night!