I used to do fitting only. But this pushes flux into the pipe/fitting & contaminates the central heating system/hot/cold pipe work, mixer valves, so forth, if your on a big project & pipe work is going to remain dry for considerable time it will start to degrade the pipe work internally, ie verdigris, & can be quite a pain when you keep greeting green particles floating in your basin bath water, I know your supposed to flush everything through but that don't always happen. So it only goes on the pipe now