Comment by jerkstate

I've done a lot of tinkering and repair of home electronics and appliances and usually the problem is a blown fuse, bad connector, bad switch, worn out battery, or other simple problems. Stocking these items - connectors, switches, fuses, rechargeable batteries - will let you fix the most common problems. A lot of folks have given good advice on resources to learn about electronics and ways to practice, so I wanted to offer a little practical advice about tools and supplies that I've picked up over the years.

Most important equipment is a multimeter and soldering station (with desoldering supplies), good wire cutters and strippers (I like the self-adjusting wire strippers for everything except very large and very small gauge wire), so I'll recommend a couple of additional tips I've learned; first, don't get an auto-ranging multimeter, especially cheap ones are usually not very good. I would also recommend one with a higher "count" like 6000 count, meaning the voltage and resistance measurements ranges go up to 6, meaning you have more range before you have to switch to the next higher range.

Also, I want to really emphasize the importance of good soldering materials and technique - I prefer finer solder because it melts faster and requires less heat. It is easy to destroy some more sensitive items with too much heat. Learn to recognize a cold joint, make sure to use a good flux (I like liquid flux like kester 186). Keep a wet sponge at your station for cleaning the tip, remember to tin the tip, and use a fume extractor. Also, there are a variety of "third hands" you can get, I don't really like the small ones with two alligator clips and a magnifying glass, you can get ones with more clips that can hold more things, but a magnifying glass is really helpful (although it interferes with your depth perception) - I use a gooseneck magnifying glass with a built in light ring to help me solder.

Make sure you have heat shrink tubing and a heat gun. These are great for finishing wires and much more durable than wrapping with electrical tape (although high quality electrical tape like super 33 is much better than the cheap stuff)

Finally, when you're looking at a board, try to identify how the electricity will flow. Learn to identify the ground and vcc traces/planes on a pcb and test your theories with the multimeter (continuity mode on a powered off device is best for this). Build up a mental model of how the device works, and write down a circuit diagram. Seek to learn to identify common circuit patterns and what they are used for - decoupling caps, pull-up/pull-down resistors, ESD protection diodes, debouncing filters, level shifters, voltage dividers, op-amp configurations, serial headers (SPI, UART, JTAG, etc), transistor/mosfet/h-bridges. Learn to identify your ICs and look up the datasheets (I have found that taking a picture with flash with my phone is the best way to read hard-to-read IC labels) - the app notes will usually have a reference circuit with the necessary components, and you can use those to identify which components are related and why they're there. Good luck and have fun!