Power is Heath (1/2)

Do not underestimate the heath in your system

Even if your microcontroller may barely get warm:
Linear power supplies tend to get hot
Switching power supplies are not 100% efficient, either
"Big" 0603 SMD resistors are 0.1W only
A led may draw substantial current (a Neopixel is up to 50mA)

If you run on 24V, even the resistor divider can hit you
A 1k pull-up resistor to 24V outputs 0.6W when driven low

And then the environment temperature may rise. Or fall.
The lab is warm, but sometimes the client wants more
Clients may ask for up to 70 degrees ambient temperature
Or down to -40 degrees

You may need cooling, but sometimes heathing too.