If you are in a high humidity area, every 3-4 weeks seems normal as I have also experienced that at times. Hot and humid is worse. Standing with the door open, or opening it a lot isn't helpful. Also make sure to let leftovers cool before putting in the frig, and, make sure all food is covered. Do you have a refrigerator thermometer? If not, get one. It's also possible you have the temperature set for much colder than you need which would keep the frig running more and it will frost/ice up the fins faster. Your refrigerator should be below 40. We keep ours at the 34-36 degree range.