There are directories which list residents in historic Ireland. Many are available on microfilm, scanned online or transcribed. They are important in your genealogical research. However, at what point should you use them?
My rule of thumb is if researching a tenant farmer or urban worker – don’t bother. These were not the class of people to appear in the directories. If your ancestor had a specific trade, maybe a baker or blacksmith, then yes. A trade may warrant a directory entry; even if only in the trade section.
If your ancestor was Protestant, educated and well-off, then always look in the directories. There were gentry sections for many directories. Other directories were for a given province or city.
My big frustration is when I am researching an everyday family in the nineteenth century industrial jungles of Belfast or the tenement squalors of Dublin. It would be easy to treat these areas like you would a typical North American city directory. It’s not that simple. Usually the tenement houses will be listed, but that doesn’t mean the people living in the tenements will.
Directories can be found at the major repositories in Dublin and Belfast as well as on microfilm at the Family History Library in Salt Lake City. A search of their online catalogs can help you determine if any of them cover the areas you are interested in exploring.
In conclusion, don’t hesitate to look at various Irish city and trade directories, but don’t expect them to have the coverage found in the directories in many other countries.