I agree that everyone will give you a different answer, and as each horse is an individual, they are all slightly different. On a different note, I did the string test on my Arabian, and it said that she was supposed to top out at 15.1. She's 5, and only 14.2ish right now, and while I know her line is said to be a slow maturing line, (not done growing until 7ish), I highly doubt she's going to get to 15.1. I have no idea exactly what her diet was like for the first 3 1/2 years of her life, though I know the last 6 months before I got her she was fed 1 flake alfalfa in the morning, and 1 at night. Most of her half siblings and her parents are all around 15ish hands. So not exactly sure what happened with her, but I love her anyways.