A mist-level control changes output. A humidistat responds to measured humidity. They are different features, and neither eliminates the need to check the room or clean the tank.
Match the control to the problem
If humidity is already adequate, more mist is not useful. Use a hygrometer away from the direct plume and reduce or stop use if surfaces become damp or relative humidity exceeds 50%. A large tank is not a reason to run continuously.
A documented example
The Levoit LV600S provides smart controls and a top-fill design described by Levoit . Check the exact manual’s automatic behaviour, sensor placement and warm-mist precautions. This is an example, not a measured quietness ranking or proof that it fits every bedroom.
Daily ownership
For portable humidifiers, EPA guidance calls for emptying and drying the tank and adding fresh water daily, with cleaning every third day. Follow the manual for cleaners, parts and thorough rinsing. Keep moisture away from electrical equipment and use only the approved placement.
Choose controls you can operate reliably, then confirm the capacity and physical fit rather than buying on the highest output setting.
See Also
If you want to pressure-test this shortlist, read What to Look for in a Bedroom Humidifier for Large Rooms, Humidifiers for Small Bedrooms: Avoid Too Much Moisture, and Compact Humidifiers: Balance Footprint and Refill Work next.
For more context beyond the main ranking, Portable Dehumidifier vs Whole-Room Dehumidifier and Best Mattresses for Every Sleep Style add useful comparison detail.