Disappointment. It simply doesn't work. They changed something in the firmware as I learned, and now it shows that the lid is permanently open, so it doesn't function. It requires many connections and disconnections from the power supply, countless ups and downs of the lid, and maybe you'll be lucky. For intermittent smart operation, don't even think about it; it won't start again if it stops. Better buy one for 8 euros; it's the same.

Spare filter. I do not believe in any case that you should change every month as xiaomi asks. Let's not get crazy. Although I already use filtered water, I do not know to what extent it does more work than the filter I use and for us. It definitely keeps hair, dust, fluff... This is useful for that.