It is crucial to pay attention to the smaller items during preventive maintenance (PM) as they can significantly contribute to the proper functioning of the air conditioning system. While these items may go unnoticed, they play a vital role in ensuring the overall performance and efficiency of the system. 

For instance, regularly cleaning and replacing air filters is often overlooked, but it plays a key role in maintaining good indoor air quality and preventing dust and debris build-up in the system. Dirty filters can restrict airflow, reduce cooling capacity, and even lead to system malfunctions or breakdowns.

Similarly, damaged screens or blocked intake vents can hinder proper airflow into the system, affecting its efficiency and performance. Removing damaged screens and ensuring unobstructed airflow helps the system operate optimally and minimizes strain on the equipment.

Clearing drain lines is another small yet crucial task during PM. Clogged drain lines can lead to water leakage, excess humidity, and even damage to the system components. By regularly clearing drain lines, the risk of water damage and mold growth is mitigated, and the system can effectively manage humidity levels.

Addressing these smaller items during PM not only ensures the efficient operation of the air conditioning system but also helps in maintaining a comfortable and healthy indoor environment. It prevents potential issues from escalating into more significant problems, extends the lifespan of the equipment, and reduces energy consumption and utility costs. Therefore, giving attention to these seemingly minor tasks is essential for the overall well-being of the air conditioning system.