You will need alot of photo's! just the H&S units you will need photo's of you sweeping up, working with other trades, using barriers, using signage, fire exits/stations, signing in/out of workplace, checking work area remains safe for continued work, PPE in use, checking tools and equipment is safe (i.e 110v), securing tools safely in site box/van/ locked room, materials and storage areas, proper use of barriers, signage, first aid book, RA+MS with supervisor, drawings, 3 types of access equipment and checking its safe, pics of you with the client ect ect, and thats just for H&S units. Other units you need to have pics of the equipment before and after install, measuring, laser levels, proper drill bits....... its endless. Its easier to just take a picture of anything and everything with you in the photo. Im finding its all about the stuff around the outside if you see what I mean, not just the doing it.