When to turn front facing?
I want to add that some older (and maybe cheaper) seats are not comfortable for 3 year olds rear facing. Ds2 (3.5) is rear facing in my car in a Peg Perego convertible. He will happily sit rear facing and has never complained. But in DH's car, we have a roundabout 50 (which expires this month), and I had to flip DS2 forward because he complained about being too squished (you could see he didn't fit),plus he hit the 35 lb weight limit. Newer car seats are designed so much better for RF than ones made 7-10 years ago.
DD (3/06)
DS1 (7/09)
DS2 (8/13)