A faucet with a single knob for temperature instead of mixing them yourself. Many inner pieces are not cleanable and with calcium in the water they break easily.
The ones that just let you set the ratio between hot and cold and not a specific temperature work perfectly for 10 years+ here.
I haven't been able to get a different kind, I want one where I can control both temperature and flow rate, they phased those out apparently for safety at some point.
Maybe i have super soft water, but I bought the cheapest thermo faucet about 10 years ago, moved houses with it and it works fine.
I did have to recalibrate it when we switched from a gas heater to a heat-pump, which required some violence and some cleaning vinegar soaking. But otherwise, it's been great.