Arduino + fridge = counter (?)

Projects General Guidance
1

In our family, fridge is opened a way too many times a day. I want to count how many times a day it is. Do you have any dieas how to realise it? I had idea with photoresistor inside of fridge, but I am not sure if a 4 AAA batteries can power it for a week.

And the same thing for one doors in room, but I have to do it from inside of room. I want to make automatic light. Could you resent me on some pages about if you have some cuz I could really find except magnet thing, or give advices. Thank you have a nice day

2

Mechanical counter to fridge door, maybe.

It wouldn't even occur to me to use electronics.

3

Ultra simple.

Wire up a wire/rod/pin one the door for instance and a plate on the body. Run 5v trough them. And record each time there is no contact.
Or just glue a push button at just the right distance that when the door closes the button in clicked. Od a toggle switch. Anything that can act as a switch.
The rest is just your normal push button code. With some recording component.