main problem that we had was finding something for our little boy when he was ready to move from one stage seat to the next! He was a big baby born and continued with that trend throughout meaning that he reached the weight and height limit much sooner than the age recommendation to move to the next seat. This caused me so many problems, some advisors at stores told me that i had to wait until he was the right weight AND age and then others advised that it was weight and not not. The whole thing was so confusining!
It has happened again when we have moved him out of a harness based seat, some advice was to keep him in there until he was 4, some advice was based on his weight. I specifically asked two seperate people in the same shop (mothercare!) at what point the harness based seats become unsafe, two different lots of advice, one told me that the harnesses werent safety tested after 18kg and the other said that was nonsense and he would be fine in there!
All so confusing, just wanted him to be safe and seems so complicated!