Have any of you guys ever used skilled contract labor to suppliment your regular crew on a project by project basis?

I am not talking about laborers, I mean finish carpenters, plumbers, electricians?

I had a guy contact me about a company that will send a skilled , say finish trimmer to my site with tools, and they bill me an hourly wage that includes all taxes and benefits.  The job and be a week or six months.  When the job is over the guy leaves and that ‘s it. unless I need him or them again.