These type of systems are easy to take care of when the equipment is sized and installed correctly. Typically, changing the air filter will be the only effort needed to maintain your residential geothermal heat pump system.
Like other equipment involving an air filter, a dirty filter will cause poor performance and lower efficiency. If a filter gets so dirty that airflow is severely restricted, the geothermal heat pump will protect itself by shutting down to prevent too high or low operating pressures. Most filters don't get to that point, but inefficiency isn't a desired outcome either, so remember to change your filters!