If you're like me, whenever you install a new system--an ice maker, garbage disposer, stereo system, or other item--you always have some parts left over. For example, perhaps you installed a new garbage disposer, but you didn't use the new sink flange because the old one was still in excellent condition. Or perhaps you tore out an old fountain and kept the water pump.You kept these items because, first, they would cost a lot of money if you had to buy one for yourself, and second, you never know when you or others might need just this part.
But in reality, no one (and no one's brother) ever needs that part. So it just sits on the shelf and makes you feel as if your storage space is too limited.
I save screws, among the other items. I have five or six or ten jars each at least half full of assorted hardware items--screws, nuts, bolts, custom brackets, sockets, stuff I'll never use because it's proprietary and fits only the one item I bought.
My excuse is that, "If you ever need one of these, you won't have to pay for a new one." And there is some rationale to that line of thought. A friend of mine needed a new capacitor for his home air conditioning unit. Now, I used to save old capacitors, so I took a look and discovered that my home collection was no more. However, I looked up the part he needed, a 35/5 microfarad capacitor, and Amazon had it for about $10. That is substantially cheaper than the air conditioner repairer's price of $105 plus his labor of $100 to $200.
Experiences like that make me wish I'd saved more parts. An so they mount. Of course, they are almost never needed, because either the part doesn't fit or it is no longer required, or it wears out too fast. Or the person doesn't want a used part.
So, over to the Salvation Army will go boxes of perfectly good items of all kinds.
Just for reference, here is an example of the type of capacitor I mentioned: