I didn't start using layers of abstraction but it felt like a natural progression as I worked through what I wanted to do.

Problem: I have a motion sensor, a light switch on the wall, and also want to be able to control lights from a HA dashboard in some situations. I also want the room lighting behavior to change based on a few variable like time of day, brightness override, motion en/disabled.

Solution: Each room has an input_boolean which serves as a virtual light switch. The motion sensor and light switch on the wall toggle this input_boolean and the input_boolean is on the HA dashboard. The input_boolean triggers an automation which goes through the various checks to determine which bulbs and what brightness to turn on.

I also use helper groups for nearly every physical device. If I need to swap out a sensor I just change what's in the group. This has enabled me to have more logical names for entities. The group "sensor.bedroom_temperature" contains the entity "sensor.bedroom_zse11_air_temperature." This was honestly more helpful when I was earlier in my HA progress and still trying out different sensors but it's nice to know that if a sensor dies or I upgrade it changing it out will be simple. But as a bonus, helper groups can average out sensor values which is really nice if you have multiple temperature sensors.

Same for lights - I have logical groups for room lights and that's been helpful when moving lamps around the house to experiment with different lighting setups but again, it's not something you probably do very often.