Have you walked into a room and immediately felt uncomfortable and wondered why? Done your errands and discovered you returned in a disagreeable and wondered why. What happened?
The answer is that negative energy attached to you causing a feeling of discomfort when you entered that room and in a disagreeable mood as you moved through the daily tasks of shopping, post office, etc.
Now, consider where that negative energy goes if you continue to carry it with you while you go to work, visit a friend, or return home, etc.
Here are just a few scenarios to heighten your awareness around the passing of negative energy.
Example: You are arguing in a public place. That energy exchange leaks into that space as it spreads by the spoken word. Anyone who walks through that energy you unknowing put there will be hit with that negativity and feel the effects of your anger and take it with them. Have you gone to a store in a good mood and come out in a not so good mood?
Clearing needs to be performed when:
moving into a new space
after a social gathering
after family visits
after a delivery of anything that is brought into your home
after repairman or technician comes into your home 
after a heated argument
All of these situations can have the tendency to leave negative energy that can attach to you, making you feel moody, depressed, angry or anxious. 
Reiki and Reiki symbols, Sage, Palo Santo are used to remove the stuck negative energy and replace it with positive energy. If necessary, crystals are purchased and programed by me to protect your home and placed to hold the protection indefinately unless they are moved. It's not magic, nor is it a religious ritual. Put simply, it works.
Two hours at a business, place of worship or residence.