Smart Bulbs
Smart bulbs cost more than a smart plug controlling a regular lamp, but they enable things a plug can't: dimming, color changes, and control over overhead or recessed fixtures that a plug can't reach.
The core split is Wi-Fi versus hub-based (Zigbee, or Thread on newer models). Wi-Fi bulbs are simpler to set up and don't need extra hardware, but a large all-Wi-Fi setup can bog down a router. Hub-based systems like Philips Hue scale better and tend to respond faster, at the cost of buying a hub.
White-only bulbs are noticeably cheaper than color-changing ones, and for most rooms — especially ones where you just want a schedule and dimming — white (or white ambiance, which adjusts color temperature) is all you need.
What to look for
Decide if you actually want color
Color bulbs are fun for accent lighting but overkill for a hallway or closet. Tunable white bulbs, which shift between warm and cool white, cover most everyday needs for less money.
Check dimmer switch compatibility
Smart bulbs generally need constant power to stay connected. If the fixture is on a traditional dimmer switch, either replace the switch with a standard on/off one or buy a smart switch instead of smart bulbs.
Hub-based systems scale better
If you're planning more than a handful of bulbs, a Zigbee system like Philips Hue is more reliable at scale than an all-Wi-Fi setup, which can strain your router with too many connected devices.
Match brightness (lumens), not just wattage
Compare smart bulbs by lumens output, not the old-fashioned watt-equivalent number, to make sure a room stays as bright as you expect.