Most frequently, brass hinges are used on doors, specifically exterior doors. Brass hinges are used on doors for a few reasons. First of all, door hinges must be quite sturdy, as they are vulnerable to wearing and corrosion from their frequent use. While stainless steel is as strong as brass, it does not respond well to any coating materials, and thus becomes incredibly susceptible to rust, especially near oceans or salt lakes.
This rules it out for exterior hinge use, which ushers in the brass hinge. While it is true that it requires extra treatment for salt water, brass is, on the other hand, a very sturdy metal that can withstand bad weather and many air conditions, like rain, smog and salt air. Also, brass can form thicker hinges than stainless steel.
Another thought to consider is that, though brass hinges are more expensive than steel hinges, they lend a more quality and classic look to a finished product. With ease, brass hinges lend a Victorian or antique feel to a door. They can even be designed to have some of this detailing. Brass responds very well to finishes and will retain a broad array of colors. Materials may be polished, lacquered, chrome-plated, japanned or finished with simple copper.
Lacquer is a liquid made of synthetic materials, or of shellac dissolved in alcohol. Lacquer dries to form a hard, protective coating and can be used on brass hinges to improve reliability and longevity. Brass hinges offer both a timeless look, and, strong and able weather many storms, the assurance that they will last many years.