A salt-free conditioner is not a softener. A softener swaps the calcium and magnesium in your water for sodium through a resin bed and rinses that bed on a schedule. A salt-free conditioner leaves the hardness minerals in the water and changes how they behave, so they are less likely to bake onto heating elements and pipes as hard crust. That can be a reasonable choice for some homes, but nothing on the unit tells you when it has stopped doing that job. There is no regeneration cycle to miss and no salt level to watch. Scale comes back slowly, and the first signs appear on your fixtures and water heater, not on a gauge.
What going wrong looks like
Look for changes that build over months: a thin white film on shower glass that wipes off less easily than it used to, a crust forming on the faucet aerator at the kitchen sink, a showerhead spray that narrows, a water heater that makes more popping or rumbling than before, or soap that lathers less well at the sink. Any one of these can have other causes, so the useful question is whether the change started after the conditioner was installed or after its media was last serviced.
Test before you assume the unit is working
Hardness is the number that shows whether the water itself has changed. Use a hardness test kit on a cold water sample taken before the conditioner, if you can reach an untreated tap, and again from a tap after it. Write both results down with the date you tested them. A conditioner that is working should not change the hardness reading much, because it is not designed to remove the minerals. What you are really checking is whether scale is still forming on surfaces, so pair the test with a visual check. Clean one faucet aerator completely, let it sit for a few days, and then inspect it for crust. Repeat the check on a shower head and on the glass door. If the crust returns at a steady rate, scale is still forming, whatever the conditioner is supposed to be doing.
Questions to ask before you accept the unit
Ask the provider what the unit does to hardness and what it does to scale, and get both answers in writing. Ask which part wears out, how often it needs service, and who performs that service. Ask whether there is an indicator, a flow check, or any other way you can tell the unit is still working between service visits. Ask what hardness reading you should expect after installation and what reading would mean the unit is not performing. Ask whether the warranty covers scale damage to fixtures and appliances or only the equipment itself. If a provider cannot answer these plainly, that is a useful signal. Our methodology page explains how we review providers, which can help you judge the claims you hear.
When to stop relying on the conditioner
If your hardness test reads the same as before and your fixtures keep building crust, the unit is not doing the scale job you bought it for. Stop assuming it will, and talk with the provider about the options that fit your home. Those might include a unit that actually reduces hardness, a different conditioning approach, or a plan that accepts the scale and manages it at the fixtures. Do not wait for the water heater to make the decision for you. Scale inside a water heater reduces its efficiency and can shorten its life, and it is much cheaper to act on the early signs at the faucet than after the heater starts to struggle.