Warning signs if Passport going bad? Tightness of warranty deadline?

I have a 1T Passport Ultra purchased May 22, 1916. Having unrelated problems with my computer, I called Geek squad June 10, and they informed me my Passport was damaged and I should unplug it immediately. I had had zero indications of any problem and wonder how a non-tech person like me is supposed to know it is about to crash, taking all my data with it. Yes. it was almost full. I am also wondering if there is any chance the warranty might be honored, since this awareness came not long after the warranty anniversary, and the damage had presumably been there for a while. It seems absurd to me that an ext hard drive can not last for a year. Now I have a bad one and need to replace it, how do I protect myself from the same thing next time?

Why are they telling you it is damaged? Is there a physical dent or what are they basing this assessment on?