Its more the effect on appliances etc at home
Then a ion exchange softener is the way to go, unfortunately. I bought cheap for my first softener, only £500, and it only lasted 5 years. Looked nice on paper, LED display showing litres remaining before recharge, dual cylinder, supposedly "quality valves" but after 4-5 years the seals wore on the "quality valves" causing valves to jam. Failed due to poor design, having rubber seals with full mains pressure one side and nothing on other side, means rubber seals are always pushed hard sealing against moving components. No replacement parts available either. Eventually the electronics burnt out when both valves jammed. Modern, especially electric free softeners, have mains pressure water on one side of any seals and soft water pressure on other side, meaning seals are not pressurised against moving parts, thus don't wear out.
Mine is fitted into a cupboard in the kitchen.
Anyway the Twintec, even though over twice the price (+more for fitting), has no electronics, runs solely on water flow. All valves are in soft water so no scaling and jamming. Uses the very very very much easier to handle 4Kg salt blocks, so much easier to load than trying to decant salt tablets from 25Kg bags. Also uses much less salt than the previous tablet based softener, so despite 8Kg costing me £4 for block salt it is probably cheaper than my previous 25Kg for £10 salt, I estimate it uses only 1/3 or less block salt than previous softeners tablets.
Highly recommended, clean scum free baths, crystal clear glass on shower enclosures, no scale on sinks, no scale in toilets, 100% clean scale free shower heads, soap and shampoo last ages.
I did actually have a problem with my TwinTec after 9 1/2 years, low flow/water pressure through the unit, on one of the cylinders. As it has 10 year warranty contacted local supplier/installer/repairer who said there were issues with 10 year old softeners with the sieves in the cylinders coming loose and the resin granules escaping and blocking the valves. Any way replaced both cylinders and all the valves (virtually whole lot, but paid £100 for labour) under warranty and warranty extended until 2027. Bargain.