All aspects of heating, cooling and ventilation in residential homes. I work on and have worked on every single brand of equipment thats out here. Its all the same really. Some just more bells and whistles. Lol. Ive been doing and learning heating and air conditioning my entire life. Since i was 15 years old. Im now 40. Just finishing up my 25th summer in this line of work. I have always been a “if its not broke yet, let it go” kinda guy. Sure ac and heating parts show wear and tear and there are ways of telling if a part is damaged enough to fail soon or if there's a chance it can make it a little bit longer. Some parts can appear a little worn and pull a little on the high side of amp draw but still remain intact and working properly throughout the remainder of the season. Im all for keeping an older unit going but when you have to continue with repairs it becomes more expensive in the long run. Equipment that is 15 years old and older are a huge strain on your electric bill just because of the shear age and lack of maintenance with most older units. Having an ESA/ Energy Savings agreement will help extend the life expectancy of your equipment and prevent future failures down the road. Not to mention the savings on your electric bill every month just by simply getting the equipment tuned up and maintained twice per year. It’s extremely important to have the coils on the outdoor unit cleaned and the heater checked by a licensed professional to ensure proper efficiency from the equipment. I always recommend replacing 15+ year old equipment that has suffered a major failure. Its just not worth putting 1.5-5k of repairs into such an old machine thats only driving the electric bill. New equipment installation will cut your electric bill cost in half plus you receive 10 full years of manufacture warrant and financing is always available with low interest rates. The savings on your utility bills after installation of new equipment will more than pay the financing cost.