From a high level, small plumbing repairs are easy: screw hoses together, water flows down hill. The devil is in the details and oh boy is it quite a devil. Parts are often rusted in place. Trying to shut an old valve can just as easily create an additional leak. In many American homes, working on a kitchen sink is especially difficult because it is built into a narrow cabinet and there may be a garbage disposal and dishwasher hookup getting in the way.