Our collection has Leadville City Directories from 1879-1918 (no directories for 1893 and 1896). These directories have alphabetical listings so you can look residents up by last name, and typically learn their address, place of work, and occupation. Generally the head of the household is listed for a family, however widows, working women, and adult children at home may also be listed. You will also find a business directory in the back of the directory. City directories are useful as they were done every year (with the exception of 1893 and 1896), whereas the census is done every ten years. This can help you trace the exact years your ancestors were in Leadville (or wherever you are researching). Our directories are digitized and can be accessed via this link.
Here is a page from the 1885 Leadville City Directory. If we look at Albert Swanson, we see that he is a laborer for the La Plata Smelter, and he boards at 418 W. Chestnut Street. As a bonus, Horace A. W. Tabor is listed on this page, as he has an office in Leadville at the Opera House block, and his residence is in Denver.