We live in Tampa and full time. I have experimented with the cooling settings on our fridge. It is a Dometic 2 door. As others mentioned leaving the door open and fully packing the bins causes frost quicker. What I have found is that having the unit on 3 instead of 4 or 5. Everything stays frozen, or cold on 3 and we can go about 6 months without having to defrost. Since we live in Tampa we do have to run the AC all of the time, but we do have a few days when we can leave the windows open. Even with the humidity we don't have an issue with frost.