White crust on the faucets and spots on every glass.
What hard water is, what a softener actually does, the types on the market, and what a system and its upkeep cost.

What a water softener costs by type (salt-based, salt-free, whole-house), installation, and salt and upkeep per year; what a normal quote looks like. Dated sources only.
Labor only: what changes the price (existing loop, drain, electrical outlet, permit) and the fair range.
What a whole-house unit does that a point-of-use filter cannot, sizing, and installed price.
How to choose: grain capacity from hardness and household size, single vs twin tank, certifications.
What a softener does, how to tell you have hard water (scale, spots, dry skin), and whether you need one.
What 'salt-free' really does (a conditioner, not a softener), who it suits, and the price.
What a filter shower head can and cannot do compared with a real softener; a small part with a dated price.
Pellets vs crystals vs potassium, how much a household uses, and the cost per year.
What upkeep a softener needs (salt level, salt bridges, resin life) and what a service visit costs. No repair steps.