After our contractor installed the new shower system (which looks fantastic!) and we started using the bathroom, a leak developed in the room below the shower.  After opening up the wall, our contractor found that the leak was from a bad weld on the shower arm for the rain head.  I have to replace that, re-repair the wall, and pay to have a new one installed.  The replacement part from a local plumbing store is about $100, not including the labour and materials to fix the damage done.