How much Work is too much?

How much is too much? At one time when I was younger I was working 60-70 hrs a week, but would burn out often. Since high school when I have worked full weeks I have never usually worked less then 45 + hours a week.. If that too much? And what do I have to show for it? Nothing.. well now I am saving my money so my $$$ is growing but you would think I have something else to show. So how much do you work a week and do you think it is too much?