While most, if not all, sites will employ general labourers who are usually the ones to keep things clean and tidy around the site, it is still everyones responsibility to keep your work areas clean and safe from various hazards. Not putting tools away properly (like a table saw, making sure the blade is retracted) could be very dangerous things people could trip over, or even land on. Making sure you clean up after yourself diligently so there aren't hazards like excess dust, extension cords and materials laying around, or chemicals that can be spilled is a good habit to get into. Saying to yourself "it's not my job" just puts others at risk until the hazard is properly dealt with.