After an unfortunate confluence of circumstances that led to her being out of work due to a long illness, Carleen Nicholson, 65, of Dover, N.H., found herself needing extra income. Then her son committed suicide and Nicholson began isolating herself. Eventually, she knew she had to do something. So for ?money and sanity,? Nicholson began driving for Uber, the nation's largest on-demand ride-hailing service.