I definitely like Scott Warrington's answer.
In spite of Scott's desire to promote sales for his company by simply giving a "yes", he is much more honest than that.
Whether a softener gives a noticeable bump in effectiveness for chemical activity or scale reduction in heating systems, is wholly dependent on what kind of hardness exists in the native water.
As a general rule, anything over 3.5 grains of hardness per gallon, indicates that a softener will have a noticeable , beneficial effect. The more hardness, the greater the savings to the end user(you).
Then you have to decide which kind of softener to get. A manual softener requires repeated filling through a narrow opening, with manual disconnect for backflushing and recharging. There are also semi-automatic models that take some of the labor and time required for the recharging cycle. Fully automatic models simply require addition of salt to the brine tank and minor operations to set the recharging process in motion.
The greater the automation, the more the initial capital expense. But that initial expense may pay-off quite quickly for some users. The premier units, like the Kinetico are real labor savers for high-volume water softening.