Many use the general term of conditioner to indicate softener or a filter as well. They all are form of water conditioners. The conditioner is a generic term for water treatment normally at your home. In its basic form it refers to straining or filtering dirt and other particles out of your water.
Water in your area may not be the same as another area. Some area water is extremely hard and could contain 30 grains per gallon or higher. The measurement indicates the weight of hardness of minerals in the water. The Geological Survey of the United States (USGS) considers 10.5 grains per gallon is extremely hard.
There are minimum government treatment standards before water reaches your home. Chloramines replaced Chlorine as the main disinfectant in our water in many communities. Since many communities are getting majority of their water from water wells, the water we use is extremely hard. The change in chemicals to treat water creates many issues for homeowners with water heaters due to increased sedimentation and others in many communities. Water heater failure is one big issue many homeowners face today. For communities with hard water, water conditioners may help with the issue to a certain degree.