We never used one at home, but bought a side rail for visiting and traveling after an unfortunate incident in which ds fell out of bed in a hotel room and hit his head on the nightstand. (*Pain* still, when I think about it.) Our set up at home is very secure, with the bed snug against the wall, and not on a bed frame, so we never needed the rail except when away.
We moved dd into our bed when she was a couple months old---she had been in a bassinet right beside the bed. We had a queen size at that point ( 2 adults 1 babe and 2 cats) dd slept in between us, I did get a guardrail in case she was ever on the outside but mostly it kept ME from falling out of bed ---I also have one for travel that folds up really compact, both are mesh inside a padded metal frame.
We just retired our cosleeper because dd (7 mos) was waking up every 1 1/2-2 hours after we put her down in it. She'd fall asleep as we lifted her to comfort her, then start crying as soon as we put her down. I started just leaving her in the big bed after she nursed to sleep and she slept for 6 hours! The only problem is that we have a futon bed frame which means that we have a mattress but no box spring. I haven't found a rail that will work on it. The top of the mattress is only about 20 inches off the ground. Does anyone know how safe this height is, or if it's possible to get a rail that works on our bed?:
we got one and it was stupid and pointless. she was 9 months old when she squirmed up to the top of it and fell out of the bed anyway. we disassembled it and put it in the closet the next day. we now sleep on mattresses on the floor.