The fridge in the rented condo apparently is an old model which does not have the frost-free feature so defrosting regularly is a must. However, those 'clever' or careless housemates of mine likes to open the fridge and not close it properly allowing room air to enter the fridge.
The fridge is also some how weird. The opening for the melted ice, water, is somehow blocked for whatever reasons I have no idea. So, if the defrost button is pushed and the defrosting process is allowed to take place, water will leak out of the fridge. This happened quite a few times.
Just today, I defrosted the fridge as the ice in the freezer is so thick..no thanks to their carelessness. This is how much ice is removed manually by hand:
Although it cant be seen, there are chunks that are about 1 inch thick.