There are benefits for both builders and laborers in using construction employment agencies, construction recruitment agencies, or construction headhunters.
The benefits for builders if they choose to use these types of agencies include decreased costs, less time spent on paperwork, and the fact that most of these agencies have their own contracting licenses. They’ve also presumably tested and vetted the laborers that they send out to the builders’ jobs, so the skill level is known before the laborer swings his first hammer or cuts his first board.
The benefits for construction workers in registering with these agencies are that the agencies hire them, the agencies pay them, and the agencies are responsible for workmens’ compensation insurance policies. The agencies may even be able to mediate if the builder and the construction worker are having work-related issues.
Another benefit of registering with an agency is that when it comes time to look for a new position, you have a name, address and phone number to supply for references. Sometimes, builders can be very transient and travel all over the country chasing after jobs; this can make them very hard to find when it comes time for that reference. Besides that, they’ve probably hired hundreds of people before and after you, and unless you were incredibly bad (or incredibly good) they may not even remember you.