Why use addons?

First, there are so many addons in home assistant. Many of them can be found on the "add on store" called HACS (home assistant community store).

This expands the capability of home assistant greatly.

Here are a few that I think are worth looking at.

Lighting

Magic Areas

This one is pretty awesome, it basically will auto set up motion/presence based lighting around your house. It also includes some nice "sensor merging" where you can use multiple temperature sensors and etc, merging them at the room/floor/house level.

Adaptive Lighting

This one will auto set light temperature based on a lot of fancy rules, but you don't have to think about most of them. You want dimmer, warm lights at night, and brighter ones during the day? Install it and go.

Others

When I get un-lazy I'll list more here.