Less than 1 week –
Less than 10 hrs/week –
There's a built-in Windows feature called MouseKeys which is an option for people who have physical disabilities to control the mouse movement and control from the keyboard. It can be found at http://windows.microsoft.com/en-US/windows7/Use-Mouse-Keys-to-move-the-mouse-pointer. There's another program called NeatMouse (http://neatdecisions.com/products/neatmouse) that offers similar functionality.
The problem with both is that they sometimes don't work in certain applications and games for whatever reason. Most often the movement works but ...