I have heard that they can live around 20 years in captivity and sometimes longer! A good guess is that the average lifespan is around 15 years. I had a frog that was 9 years old, she passed away to an unknown illness. If well cared for these frogs will be a long lived companion.
It takes them about 7-12 month to reach full size from froglet stage. Water quality, correct diet and tank size encourages proper growth. Poor diet, too small a tank and/or overcrowding and unclean water can cause stunting in their growth and other problems such as bone deformities, illness and even death.
Once every 1-2 weeks your frog will shed it's skin. It will appear as a transparent film hanging off its body. Then your frog will kick at its head a few times to remove the skin. Usually when this happens the frog eats the skin. It is a fast process lasting less then a minute and sometimes you may never see your frog shed. Sometimes frogs wont eat their skin and you will find a thin filmy substance stuck on tank decorations. This is the skin that was shed so just remove it from the tank and throw it away.