I went out for PM, and filters. One roof top unit (4 ton Carrier, if I remember) wasn't cooling well.
I offered to clean the coils, totally needed.
They replaced the entire unit. I got back to the store, and there was a whole brand new HVAC with gas heat and all.
So, if the car needs a tune up, you junk the car and buy a new one? I'm astounded at replacing a roof top unit because it's dirty. Seriously unbelievable.