I only found this out the other night because my fridge went dead silent for a long time. I thought it was borked, so I was peering deep into the freezer when I saw The Gates of Hell through the grate.

(Okay, so full disclosure, I had smoked some pot, but it totally looked like when Dana opened the fridge to Zuul before she was The Gatekeeper.) 😱😱😱

Anyways, turns out it was in defrost mode (which happens twice a day), and that involves some elements going orange or something. I know that's vague-- I looked it up, but as I mentioned, I was high, so I only kinda remember, lol.

Edit:

The refrigerator activates a heating element located near the evaporator coil. This element warms the coils, causing any ice buildup to melt.

That is assuming they are in good working order with no broken seals anywhere. They will run continuously if they never manage to get near the target temp. Though in that case, your food is probably also not getting refrigerated and you hopefully notice.

Tbf computers also have a sleep mode.