If you keep your phone at 100% brightness every time you use it, then you will burn the organic stuff. Typically they last for many many years & you'd have another phone way before you would see this.

Others can drop in their experiences but I've used and still use various amoled screens from Nokia & Samsung and no burns here - the screens are as good as new.

The notification bar is always there though, so I can see how keeping the screen on constantly would eventually burn that area.