Before I had a child, I had no idea how important car seat safety was. I guess I just figured a car seat is a car seat and as long as your child is in one, it doesn't matter if he/she is facing forward or back, because they'll just be safe.
People who know me know that I am a research FIEND. Before I do anything (especially when it comes to safety in cars -- I mean, seriously, I just don't trust other drives that much) I research it to death and implement the best and safest plan into my life. Having a child has only amplified this urge and that is how I came across extending rear-facing (ERFing).
Now, we all know that infant carriers are to be exclusively rear-facing (RFing). And we may all have heard the previous AAP recommendation that it is ok to turn your child around to forward-facing (FFing) when your child turns 1 year old and is AT LEAST 20 lbs. Did you know the AAP recommendation has changed? It is now recommended that children stay RFing until the age of 2 years old (in a 5-point harness convertible seat -- NOT a booster! Those aren't appropriate until school age), and preferrably until the maximum weight and height restrictions of the car seat. Charlotte is almost 14 months old and still rides RFing in a Britax Marathon. This particular seat RF up to 35 lbs and about 49 in tall (well, as long as there is about an inch or so of seat left above the child's head) and FF up to 65 lbs! She'll be in 2nd grade by then, ha.
Following Char's current growth, she'll probably outgrow RFing due to her height before her weight (she is a skinny minny!) But my plan is to leave her RFing for as long as possible. It is shown to be over 400% safer than FFing. Actually, we would ALL be safer RFing, but that just isn't compatible with driving. :)
I'll get off my high horse and just say this: Leave your child RFing for as long as possible, preferrably until your child outgrows the height/weight limits of the convertible seat. Even a minor forward end car accident can cause serious trauma to young necks/spinal cords (internal decapitation -- doesn't that just sound scary?) if the child is FFing prematurely. Yes, it is easier to strap a toddler in FFing, they see better out the window, etc but it is definitely not safer and just not worth it, if you ask me.
Check out these Youtube! videos and google "extended rear facing" for more info.