You should always look for one with condenser tubes that are easy to reach/clean. Ask the salesperson to show you, or just remove the cover yourself and have a look. The plastic cover on the front of the machine, right near the floor. Also look for mechanical controls (avoid electronics). A good old plastic dial wth numbers painted on it beats a digital display screen (when its time to get it fixed).

In olden times and on older style models they still have those black tubes running top to bottom, side to side, on the back of the fridge. Those kinds of condensers need less dusting. But some new designs put the condenser under the fridge. They sometimes put a fan (raising power consumption) under there to blow air over the condenser. This will pick up dust from the floor and deposit it on the condenser. This means the fridge is now very inefficient. It will consume lots of energy then die prematurely and end up as waste in a landfill.