Apps can help you set up a binding commitment. Pact, an app available for both Android and the iPhone, is an interesting new option. With Pact, if you don’t meet your commitment – whether it’s going to the gym or eating enough vegetables, your credit card or PayPal account will be charged at least $5 (about 31 yuan, but you can raise the bar to $10 or even more). If you manage to keep your commitment, you get a reward between a dozen cents and $5. The reward money comes from the accounts of those weak souls who can’t keep their contracts. The app can sync with fitness trackers such as FitBit and Jawbone. It also uses GPS and photos to prevent people from gaming it.