TIL that water softeners can shorten the lifespan of a water heater.
https://www.prattplumbing.net/how-a-water-softener-system-can-affect-your-water-heater/
@sharkNserg Well yeah, but as the article details, you just need to check and replace an anode in the water heater more frequently. The anode is used to remove corrosive elements from the water.
@Zauberin There's not really much of a choice to be made there though, is there? You can't really safely forego water softeners when you live in certain areas.