Should I turn off the microcontroller when I write code?

[cockatoo]

When I write code, should I keep the microcontroller on, or turn it off and only turn it on when I want to test the code?

[mfgkw]

This will make no big difference.

If you run it from battery you can save its capacity (especially if you have a LCD connected).

Besides of that there is a really small impact on your personal CO2 footprint, depending on how long you code.

Regarding the MCU's expected life time it will exceed my remaining lifetime by far.

So who cares?