There was a similar use case I read about here on HN that interested me: using color-changing bulbs to shift the color tone of all lights in the house from cool

There was a similar use case I read about here on HN that interested me: using color-changing bulbs to shift the color tone of all lights in the house from cool during the day to warm at night. But, as you mentioned, it would be pretty expensive to replace every bulb in my house, so I haven't considered it. Maybe when I start running out of spare bulbs I'll think about implementing this.