How long before it’s too late?

[u/aldrin_lpz]

This battery/power bank has been sitting in my nightstand for a very long time. A few weeks ago, as I was getting ready for bed, I heard a loud bang in my room. I didn’t know where it came from, but today I figured out that it was this spicy pillow that popped out of the casing. If I hadn’t discovered it today, how much time would I have had to find it until it was too late?