OP, last year, we had a team of workers outside the front of our house working to rebuild a porch on our home, and Archer was, naturally, 'suspicious' of them. To this end, whenever they arrived we brought him down the side of the house, made sure he saw them all, and thereafter took him for a walk, meaning he had to both leave and enter his home past them, by the second day he was oblivious to them, albeit he would bark when they arrived, but again, that was walk time and return time. He would never have let one of them down the side passage, but as far as he was concerned them working out front was clearly not a problem to me, so why should it be one to him.I think it really helps to 'introduce' a dog to regular workers, and try to relax around them and make it seem routine. In this way the dog looks to you how to respond, and it really solidifies the trust you have in each other's judgement. Either way, best of luck!