Dave, I will leave equipment of varying natures at a job site no problem, depending on the location. All I can say as far as security goes is... Lock all the doors, and take the keys. If possible leave the stuff out of site, ie; behind the house / behind some bushes / trees / etc. Try to talk with neighbors if the homeowners aren't around on a normal basis. They will call the cops if somebody is there late at night making lots of noise. If you are doing land clearing or landscaping for a whole new subdivision; leave your stuff WAY back in the woods where whoever is gonna take it would have to go out of their way a ways. Also make it a policy on these types of jobs to get the names of everybody who comes to the site. I know it sounds like a real pain in the butt, however just keep a list of the people who come to the site each day. Get their name and driver's liscense #. This way if something should turn up missing... you as well as other contractors working on the site have a way of starting to track down the stolen articles.