How fast do tortoises age?

In my experience, males don't grow too fast and for females, it depends. My female basically exploded for the first few years of her life, and now it's pretty slow, but I think she still gains some. The little one only grew about 1 pound heavier over the past 3 or 4 years, so she still looks like a baby. (She eats all day and I'm still waiting for her to hit the 1 1/2 pound mark.) If you want a big healthy one just get one that eats well as a hatching (like my big one) and you'll be fine as long as you feed it right.