Murphy's Law of Spares
"If you buy just one of something, you will surely break it almost immediately, but if you buy one or more "spare" items to have "just in case", your "initial" item will miraculously escape damage no matter how many mishaps you endure, and thus those duplicate items will merely gather dust in the garage or at the back of your desk-drawer."
I have always tried to handle objects gently and carefully, but due to extreme forgetfulness and physical/mental/emotional infirmities, I tend to "be rough on my stuff" --- sitting/stepping on unobserved items, blundering into objects as I'm groggily stumbling to the bathroom in the middle of the night, soiling items or spilling/dropping stuff, etc., and so I occasionally attempt to "prepare for the future" by acquiring spares of the types of items which I typically seem to damage or break; only prob is that just as soon as I do "lay in for a rainy day" like that, the "currently-being-used" object that I had been procuring said spares for NEVER SEEMS TO ACTUALLY SUSTAIN SIGNIFICANT DAMAGE, and so all of those extras that I'd carefully tucked away just "sit there for decades"... talk about a classic case of "Murphy's Law of Spares"!