The single biggest problem with these refrigerators is the defrost drain hole stopping up.
Make a drain heater from a 6 inch piece of bare copper wire. Wrap it around the heater and insert the other end into the drain hole. This will help keep the hole from freezing.
Secondly,use metal tape and tape the defrost drain trough down thoroughly in the front.
Third,when you set these refrigerators up in the apartments,adjust the front legs so that the refrigerator tilts to the rear.