Tools of the trade?

Did a favour for a neighbour today and changed some lights for her. Fittings and switches. Sat down just after tea and the doorbell rang. Outside was an irate woman with no lights. Cue, straight into action and problem found in 5 mins. Lights back on and new switch will be procured tomorrow. She was very happy about what I did and how I knew where the problem was. As she lives alone, she was most grateful. At least she has lights tonight.