We turned DD1 around at 5 1/2 months because we were told her length was good as well as head control and weight, and we hadn't seen the clip (this was 5 years ago). We had to return the capsule and bought a forward facing seat only. I wouldn't recommend it as I watched the clip a few weeks afterwards and freaked out, I was going to exchange my car seat and never did... it freaked me out for months.
DD2 was turned around at 13 months. She was taller than the straps and I had to do it, I would have kept her there until 18 months ideally, but she was too tall.
