We have had several softners over the years, all fail sometime, just like any appliance.  Currently have a Culligan, and it works better than others we have had.  I like the suggestion of Kinetico Mbmaring mentioned, I hadn't heard of it when we bought the last culligan about ten yeas ago.  I would look into that brand if and when I need to replace the one I have, is advertised to use less salt.  Currently we use about 70 pounds of salt a month, seems like a lot, but the container holds about 400 pounds.  Worst part is getting the salt into the basement.  Wife and I notice water doesn't seem as soft as it once did, so perhaps it is close to needing replacement.