The dirt and debris build up on this coil and blower wheel are perfect examples of why it’s so important to change your filter every 30 days.
The dirt on the coil acts like an insulator affecting the overall operation of the system. The compressor works harder than it should and the system runs longer which translates in to higher power bills. Ultimately the additional stress will lead to failure of the motor.
The dirt on the blower wheel acts like a weight on the motor, this causes higher amp draws and reduced air flow. In addition to the mechanical aspect, all of the air in the home passes over this dirt and debris. Air quality is an important factor that is overlooked most of the time.