Many factors can play a role in figuring out how many sets of brake pads you need for front brakes, the simplest answer is “it depends”.
Sets of brake pads do I need?
The condition and thickness of your old brake pads will determine how much pad you have left to work with. If your old brake pads are worn down to nothing, then you only have one set of new brake pads available. If they still have some life in them, then you may be able to get away with using one set for your front brakes and maybe even another set if the rear ones aren’t too bad.
In addition, don’t forget about your disc rotors! The bigger issue here is that if you use two sets of brake pads on the front and not enough on the back, then you risk overheating your brake fluid with no hope of cooling it down. It is very important that the disc rotors are evenly heated when braking or else they can warp, which will cause an expensive repair job. And running out of brake pads doesn’t stop there, if you aren’t using new brake pads on both front wheels then you run the risk of uneven wear and poor performance.
If your vehicle comes equipped with ABS (anti-lock brakes) this adds another layer to the number of sets you need for front brakes.
Some manufacturers recommend replacing your brake pads in pairs at a time because having one set worn down while the other is brand new could cause binding problems between the two separate systems. Replacing them together allows them to work smoothly together throughout their life.
How changing brake pads affects performance positively?
If your brake pads are not suffering from any of the issues above, then you may get away with replacing only one set, but it’s always safer to replace both sets at the same time. Doing so will net best performance and safety out of all your brake components by protecting against uneven wear and overheating of your fluid. If you have aftermarket or upgraded brakes such as drilled and slotted rotors, they must also be replaced when changing brakes in pairs if they were made with the vehicle otherwise steering and suspension components can fail in a fraction of a second.