I use hot water from my steam boiler for a 500ml Thermos of tea each morning. The hot water tap on the Vivaldi is solenoid based. As soon as I'm done filling the thermos, I turn the steam boiler off, which also stops the refilling process. The machine is on a timer; when it gets turned on again, the steam boiler gets turned on also, filling itself with fresh water.
I also use it to preheat cups every morning / evening.
I also use the hot water tap from time to time for cooking.
The water then get flushed quite frequently.
As my steam boiler is made of copper (unplated) and as I wasn't able to find scientific evidence (yet) that drinking water daily from such a boiler would or not pose a long term health issues, I also do this flushing routine in a precautionary principle point of view.
For the same reason, I prefer to keep some scale in the boiler and to avoid doing unecessary descaling (first having a look inside the boiler every 6 months).