Some of the most important refrigerator maintenance tasks are well within the abilities of the average homeowner. Checking door seals, cleaning the condenser coils, maintaining an adequate cargo load and keeping the temperature correct all contribute to the life of the appliance.
Refrigerators require thermal mass, which means plenty of items inside, to keep temperatures low. Cold drinks and foods soak in the warm air that enters when people open the door. Even storing some gallon water jugs is a good solution for people who don't keep much in the refrigerator.
Regularly testing to see if a dollar bill sticks when closed halfway into a refrigerator door is a good check of the door seal. Rolling the fridge out a couple of times a year, unplugging the unit and vacuuming the coils increases the efficiency. Keeping the freezer temperature at 0 degrees Fahrenheit and the refrigerator between 37 and 40 degrees Fahrenheit is ideal as well.