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.
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.