Use of dried white sage is a 2,000 year old Indigenous practice. The shamans used dried sage plants on their fires as a ritual of calling upon ancestral spirits. Any conflict, anger, illness or evil was absorbed by the sage smoke to be released or cleansed from the energy field of a person.
Some ideal (or necessary) times to sage your aura and/or space would be:
When you move into a new living space
When you begin a new job or start your own business