If you keep their temps nice & warm with lots of yummy food, then they can grow pretty quickly. Mine ranged from 1/2-1" when I got hem in mid-Nov & by Jan the males started sporting their wings....I kept mine the same temp as the gecko room so they grew a little slower. I have since moved them into a warmer room to hopefully get them to start breeding. If their temps are to cool (70's) they won't breed, so have they now have a east facing room that gets a lot warmer due o afternoon sun.