A friend of mine recently told me his kid’s iphone warranty was viided because they used non-apple HEADPHONES!!!! Whata racket.
Nothing like foolishly buying something that will never actually fully belong to you and forever belongs to the maker.
Not me, ever... It’s stupid.
Your friend lied to you. Apple sells multiple makes of earphones in the Apple Store. . . and online. Apple doesn’t care what peripherals you use with its devices. You can void your warranty with a non-Apple charger if it damages the device. You can even get yourself killed by using a non-Apple charger. That’s actually happened.