Fix don't toss those old tools
It's honestly not hard to fix your own power tools. While the Home Depots of the world would love for you to toss that old broken screwgun and upgrade to a new one, the reality is that it's much cheaper (and better for the environment) to keep the old workhorses in service.
The first issue that older cordless tools face is poor performance when the batteries start to go. They don't hold a charge, and are a lot weaker than they used to be. Maybe your cordless tool is a little old, and the local shops only offer the newer styles of batteries for the new tools and everything's upgraded now, so you're stuck thinking that you just need to buy a whole new tool. However, plenty of companies online offer batteries for older tools, such as lowcostbatteries.com. New batteries will make your ten-year-old screwgun feel like new. It's simple, and honestly, your old batteries might be a lot weaker then you realize for you've gotten used to their lower output. Recycle your old batteries properly, and get new tool performance for way less money and way less overall waste.
Next up is gunk. You've been working hard with your tools, and they don't always get the cleaning they deserve. Also it's a bad habit, but you sometimes hold a tool in a way that blocks it's vents and works dirt into them. If your tool smells funny when you use it, or is just weaker than it was when you got it, it's likely that it's just full of dust and dirt. Cracking open it's case (while it's unplugged of course) and devoting an old toolbrush to the task, along with a little spray electronic cleaner & some proper lubricant (we like silicone), you can really bring a tool back to life. Or at the very least exorcize the bad burning smell. Always check prior to cleaning and lubricating that the chemicals you're using are compatible with your tool, and always use those chemicals so they don't wind up in you too (i.e. use proper gloves & masks!).
Now, when something is really broken, it's not like you can just go down to the hardware store and buy parts for it. For example, one of our screwguns was dropped, and it cracked both the battery and the body of the tool itself right by the trigger. I've had that screwgun for ten years now, and I'm not gonna give it up lightly. The battery was easy to replace, but the tool body itself is cracked, and cracked in a way that's messing with the trigger and not easy to epoxy. So you'd think it's done for. But a quick visit to Toolpartsdirect.com, and a new whole tool body is on the way. Transplant the older guts into the new body, and you've got a new, fully functional screwgun that even looks new for about twelve bucks. Toolpartsdirect.com is also a good resource for bushings and bearings. When the tool's getting really sparky, or when the 'magic smoke' comes out, and it stops working, it can likely just be a bushing or bearing. They honestly aren't hard to replace at all. Electric motor brushes are designed to be replaced, and some even just clip into place. And a lot of bearings are just pressed onto the shaft of the tool, and with a sacrificial block and dead-blow hammer can be mounted easily. Toolpartsdirect.com also has the tool diagrams, so it's easy to identify parts, order them, and figure out how replace them.
Finally, being American, and a Maker, it's not just enough to fix something. We've got to make it better. This is where places like skf.com & mcmaster.com come into play. Our CNC Router is the cornerstone of our shop. The better it works, the better we all work. We recently replaced the cheaper, decent-quality bearings in our router with high-quality SKF bearings from Europe. The tolerances are better, so our cuts are more exact, and being properly sealed and made of precision materials there is way less heat build-up over time. Better bearings can have a huge effect, and it's one area that sadly suffers by having tools made for as cheap as possible overseas. We've also added a vacuum hold-down table, aluminum t-slot track, and will soon be adding some auto rail cleaners / wheel lubricators
Now just a word of caution. Power tools can injure you, especially if repaired incorrectly. If you don't feel 100% about doing this yourself, take your tool to a repair shop instead. Always wear proper protection when using the tool, and always test it safely after a repair to make certain it's working properly. Finally, we're just pointing you to links to order parts, and we're not responsible if you injure yourself. Now get fixin'!