Head-mounted video camera

Having a constantly-recording head-mounted video camera would be a useful source of information for any job (assuming the convenience and privacy issues can be addressed), but it strikes me as particularly useful for builders and repair-person, if this information can be shared.

Say for example you have a problem with your heating system. You call out a heating system repair-person who has a head-mounted video camera. As they investigate to diagnose the problem, they talk through what they are doing, so that the latter viewer can understand. They identify the problem and fix it. A couple of years later you have another problem with the heating system. You call out a heating system repair-person and, before they start work, you give them a copy of the video. The pull this up on their tablet and scan through to get an understanding of past problems and solutions. They are then able to understand the system quicker and fix it quicker.