• Software: Over the years, like most folks, I've purchased new versions of the programs I use. But I hang on to the old versions. In almost every case, these early versions of programs such as Microsoft Office and Adobe Photoshop don't require as much horsepower from a computer. That means they'll run on a slow, old computer you have stashed away. So if disaster strikes that fancy new PC, you can quickly cobble up a system that will let you finish a project, or just check e-mail and browse the Web until you replace or fix the ailing new machine.
• Accessories and add-ons: It's the same with old printers, video cards, scanners, keyboards and the like. They offer a temporary (or even permanent) replacements when the computer store isn't open and you have work to do. They can also be useful in diagnosing problems that crop up.For instance, if your monitor suddenly begins to flicker, the problem could be the monitor or the video card. By substituting a working monitor or video card from your junk collection, you can determine which one. If the problem continues with the substitute monitor, you can be fairly certain that the video card is the culprit.
• Old digital cameras: I use these for tasks that could harm my fancy and expensive new camera. For instance, exposure to sand and sea air — and even a possible splash or two — is just too risky for my best camera. But I can take an old digital camera to the beach and, if it's ruined, no big deal. I also keep one in my workshop and use it to make photographic notes when I take apart some machine or gadget. If I have trouble remembering where that weird-looking washer goes, I just check the "before" photo.
• Computers: We've already talked about some uses for an old computer. One that really can pay off is turning the old machine into a place to store backup data. I raid my trusty junk box for the largest hard disk I can find and install it in the old machine. Since that machine is part of my home network I can transfer copies of important files and data to that PC. I still back up my computers with external hard disks, but for files such as family records and photos, having that extra copy is not excessive.
• Cellphones: Several organizations accept old phones as a donation. Use Google to find one in your area. If you keep a phone, you can remove the battery and — if you buy or own the same model as a replacement — use the old battery as a spare. I also save the "wall wart" recharger. I have a drawer full of these and sometimes find other gadgets that can be powered with them. If you do that, make sure you use a charger with the same output voltage and polarity. (Polarity, in this case, means making sure that the positive and negative poles on the connector are correct for your gadget).
A junk collection can be a wonderful thing. Even when I don't need something to fix a problem,I can happily paw through discarded gadgets knowing that they aren't polluting the Earth in some dump.