What is considered appropriate dress code for an interview at a job site?

Although many interviews are held at a restaurant, conference room or hotel lobby, many are conducted at a job site. When meeting an employer at a casual affair such as a job site, or on Saturday, it is always imperative that a executive dress the way the employer would expect them to if hired, and take it one step higher. At a job site where no one may be wearing a suit, an executive should at least wear a sport's jacket (which can later be removed) and a business tie. Polished shoes and pressed pants are a must. An executive will be judged by the employer's first impression and to look their best shows respect for the meeting and for the employer.