Arrived to do a maintenance on a York PKG unit. I cleaned and flushed the drain line. Checked the electrical system. I checked the filter,16x20x1, owner will get new filters today and install. I recommended the following to keep the system running almost like new: The surge protector is to keep from burning up the board on the system. If you high power surges or lightning strikes in the area it may burn up the board. The start assist is toe help start the system easier and last longer. The freeze protector is to keep from freezing up the coils. If the blower fails or no air flow over the coils it will freeze the coils. The pan treatment is to keep out the algae that builds up in the drain line and pan. The Uv light needs to be replaced yearly to keep the biological growth out of the blower and coil area. The assurance plans are for the maintenance i recommend the assurance plan. We come out two times a year for the maintenance. The assurance LTE plan we come out one time