We got each of our kids a hamster when they were younger. I think my daughter was about 10 and my son was 7. While they did help out cleaning the cages, I was the one who did most of the work...but I didn't mind. I ended up falling in love with the little guys!
They're a great pet for kids...just make sure that they're supervised when the hamsters are out of the cage....they do love to take off and hide under furniture if you let them!
Their life span is 24 months or thereabouts...ours lasted 2 years almost exactly to the day. I had one of them die in my hands while I was comforting him...it was so sad. We cried and cried, but wouldn't trade the experience for anything. They had the most wonderful personalities.