1 The quoted repair cost is at least half the price of a replacement, Consumer Reports says. Tellingly, the publication only insists on repairs as "first option" on refrigerators less than 7 years old.
2 The motor is running continuously, a sign that the seals aren't holding or the compressor can't make the compartment cold enough.
3 The food isn't staying fresh, or frozen foods feel mushy even after the temperature setting is lowered. Ideally, a fridge should hold at 0 degrees in the freezer, 37 in the refrigerator.
4 The refrigerator generates excess heat. Your cat might like to hover nearby, but you won't.
5 You're still manually defrosting your box, it's time to join the 21st century.