You don't need to change rotors unless they are too thin, or deeply grooved. At 45000 miles, your discs are probably fine.
For low dust pads get Akebono Euro Ceramic:
Front Pads: Akebono EUR1663A $86
Buy two Double front pad sensors XHDZ071 for $13 each Front Disc Brake Pad Wear Sensor XHDZ071 for Audi Q5 13-17 Premium Plus Prestige | eBay
Rear Pads: Akebono EUR1547A $64
I think you need to buy a single rear pad sensor too, but I will check.
These Akebono pads have 10% of the dust of factory Porsche pads, and 90% of the stopping power.
When your brake pad wear warning light comes on, you probably have at least 5000 miles left before the pads are completely worn out. Porsche dealers and repair shops love to recommend premature pad changes, and unnecessary rotor changes, as they make more money......
I have put new pads on used rotors many times, never a problem. At 80,000 miles and above, the rotors typically will need to be replaced.
Out of which Porsche models you got those numbers?I typically get 60,000 to 90,000 miles out of my front pads, maybe 40,000 to 60,000 out of my rear pads.
Are you driving with two feet??!!??, or do you live in the Rocky Mountains??
Or your Dealer/service garage is selling you brakes prematurely...an easy moneymaker that many people get "taken" for......