I have a water softener that's probably 18 or so years old. Its apparently one
of the early demand units - goes by water usage to recharge rather than time...
It USED to work fine for three of us, but lately, even though there are only two
of us living in the house, it doesn't SEEM to be working as well.

I had the controller rebuilt a few years ago when it quit, and things went along
fine for a while, but it doesn't feel like the water is staying soft until the
scheduled gallons have been used and the unit recycles.

I recently removed the brine tank and dumped it out. Cleaned out all the caked
salt in the bottom, and cleaned out all the gunk in the tube and everything. I
watched it run a cycle and the softener did a fine job of sucking the brine out
of the tank and into the softener. I presume it was doing the right stuff in
there...

SO, since I've read in here somewhere that the resin loses some efficiency over
time, and after 18 or so years it seems we could be down to 60% or so, I figure
I could replace the softener's innards. EXCEPT, that I'd still have an 18 year
old controller that appears to be composed of plastic gears and valves and I
suspect has a limited lifespan. This SEEMS to be somewhere between $60 and $120
for parts...

OR do I just replace the softener? There are only two of us here and it seems
like our current softener cycles about once a week at 1200 gallons so it doesn't
seem like we'd need anything real big. I looked at some of the softeners at a
local place and they had a 6" that they said was good for 2-3 people, and an 8"
for 2-5. Our current softener appears to be an 8". Prices appear to be between
$500 and $1000...

When I looked at the softeners it didn't appear that the controllers had changed
much - the more reasonably priced even still LOOKED like my current one - a
couple dials on the front to set recycling interval gallons, amount of salt, and
time of day. There were also some with "digital" controllers but what's that
going to buy me given the amount of cycling we do?

Are there REALLY significant differences between the softeners, brands to go
for, brands to AVOID, or do I just run over to my neighborhood Menard's or Home
Depot and grab one...

Ideas? Thoughts?