A water softener typically lasts between 10 to 15 years, depending on the quality of the system, usage, and maintenance. High-quality water softeners that receive regular maintenance and timely salt replenishment can even last beyond 15 years. However, factors like water hardness levels, the amount of water usage, and how well the unit is cared for can impact its longevity. It's essential to follow the manufacturer’s recommendations for upkeep and to have a professional technician inspect the system regularly to ensure it functions optimally over time.