I've had corrosion. Literal rust spots forming on the metal layer. Similar to how mirrors get that mold/rust growing between the silver layer and glass. I have

I've had corrosion. Literal rust spots forming on the metal layer. Similar to how mirrors get that mold/rust growing between the silver layer and glass. I have not been keeping the DVDs in a controlled environment. They have been in a garage in a high humidity region. I think you could keep them indefinitely in a humidity controlled environment but for the average user they will corrode just like old mirrors do.