Because I usually turn the volume down, but accidentally press the volume up bottom. If it’s true that the volume can’t hurt the speaker, then it shouldn’t matter.

Maybe because I play a mobile game and the intro sound starts with a very loud sound. It was so loud the sound is distorted. I am not lying because Apple replaced my phone once and fixed the speaker another time.

Well, there are some dirt, but the holes are not covered. I’ll try to clean it later.