Even though we're on Lake Michigan water, we still have a softener. It was left by the previous owner, and to be honest, even though L. Michigan is only something like 7 grains of hardness, I much prefer the taste of the softened water, not to mention it's much easier on the tankless water heater.
Obviously, we don't have any iron/sulfur concerns with our high-quality aych-too-oh, but our softener cycles 2-3 hours every 4,500 gallons, which we have scheduled to start at 2:00 a.m.
I have no experience with whether specialized units are needed for iron/sulfur, but in terms of just the softener, the fittings are such that a DIY swap is easy... literally, shut off the main, drain/empty the unit, d/c the in/out/flush hoses on the old softener (they should be flexible or washing-machine style hoses), connect to the new unit, and turn the main back on. No sweating/soldering or copperwork should be necessary (so long as you aren't up-sizing pipes). It would still need to be reconfigured/reprogrammed, but anyone with a 4-year degree should be able to follow the instructions (or better yet, watch a YT video).