[dmcginty]

A few of my favorites:

There's a set of string lights in my apartment that were left installed when I moved in. They look pretty nice and they provide decent illumination in an area that's difficult to light, but I virtually never used them because I needed to plug them into an outlet in order to turn them on. I finally bought a device that goes between the plug and outlet with a cord to a pushbutton switch. I now use the lights daily and I have no idea why it took me 6 years to fix a problem that could be solved for around $10.

A bluetooth OBD2 monitor for my car. It can read engine codes and other diagnostics, and it can clear a lot of check engine warnings. It less than a single visit to a mechanic.

This one is way less general, but I finally bought a treadle feeder for our chickens. There were several bird flu scares over the past year and our old open-tube feeder would attract a ton of wild birds (plus the occasional rat). The treadle feeder requires the chickens to stand on a treadle which opens a cover over their feed, and they learned how to use it pretty quickly. I'm amazed at how effective it's been; we're going through significantly less chicken feed now because the wild birds were eating nearly as much as our chickens were.

[justin_oaks]

I'll also recommend getting a bluetooth OBD2 scanner. There are a bunch of them available in the $12 to $20 range.

It seems absurd to go to mechanic to know what the "Check engine" problem is.