I hate it when people compare snakes to people but sure lets run with it. Ok so people live on average about 65 years world wide. Maybe more for the US. Lets say 80 for sake of math. For sake of math lets also say humans are full grown at age 20. I had considerable broadening of my shoulders till I was about 21. Growth slows much sooner of course. So lets further assume BP live to be 24 years old (again sake of math). So humans grow for 1/4 of there life. If snakes did the same you would see them continue to grow till age 6ish. According to this pole about 28% of people have a ball python that's over 5 years old. I think you would also find that the average age of BP kept by people on this forum is well under 6 years old. So for that vast majority of people the snake should be growing. If your 6 year old snake was at a healthy weight and generally maintained that weight till it died then that would be fine. The question is really what is a healthy weight?