My house's fridge has a horribly designed freezer that is just a huge drawer with a smaller drawer inside. It wastes a huge amount of freezer space.
It also doesn't close all the way periodically. If you're not paying attention, it freezes up the coil, and melts all your freezer food.
I mounted a door sensor switch to the side and it sends my phone an email if the door been open for more than five minutes.