when I first got my s4, the home button felt great and it was really pressable, after 2 months of usage , now it feels hard and if I don't press it for a long time. It makes a weird cracky noise, is it worn out and broken ?
I wouldn't worry about this kind of stuff unless the functions controlled by the button stop working. It's an electro-mechanical switch, so it can develop mechanical problems, but that's not particularly important if it keeps working as a switch.