Flynn is 14 months old and still rearward facing in a Safe n Sound Meridian. He might just be tipping the scales at 12kg (the recommended "turn around time") but DH (who is an engineer and into checking out specs and stuff like that) is keen on keeping him that way until his legs get too long to be comfortable. From our investigations the weight.age limits are more ball park guides - if your kid is at either end of the weight for age scale they wouldn't necessarily apply IMO. There might be something in having 12kg plus hanging out in free space in a side impact (in that he might sway a bit to the side) but at least he will sway away from the impact, and I am pretty sure front-on collisions are more common. Another thing to remember is that many products are (thankfully) over engineered for safety, so it the recommendation says 12kg maximum it has probably been tested at much greater weights.