Technology used to move forward like a freight train (literally at one point), but now it's more like a 300 mph bullet train. You just have to blink and you'll miss the latest smartphone, processor upgrade, new type of connector or any dozens of other developments that never seem to stop.

With technology arriving this quickly, information about how to use it correctly can come and go just as fast. Yesterday's standard operating procedure is tomorrow's mistake. And what used to be good advice for avoiding danger might not be relevant anymore.

Today, we're going to tackle seven persistent tech myths that started out good, but that you really shouldn't believe anymore. These cover the range from battery charging to data disposal to privacy and general tech buying. How many of these did you already know?

1. You shouldn't charge your gadget overnight

Many people are afraid to charge their phone or tablet overnight because they think it might overcharge and destroy the battery. I also field this question from people worried about leaving laptops plugged in 24/7.

Fortunately, you can stop worrying. Modern electronics automatically stop before the battery overcharges. As long as you don't put your smartphone under your pillow, or stab a battery with a kitchen knife, you're OK. Learn more about battery safety and how to make your batteries last longer.

2. Don't use third-party chargers

There is a difference between knock off chargers and third-party chargers. A third-party charger is an Apple- or Android-compatible charger from a reputable company like Belkin or Monoprice. Third-party chargers are OK to buy. Just know that, in general, they won't charge your gadget as quickly or reliably as a maker’s official charger.

Knockoff chargers usually don't have a brand name, or they say they're from Apple, Samsung, HTC, etc., but have a ridiculously low price. Knockoffs are often responsible for the horror stories you hear about gadgets bursting into flames or electrocuting users. Avoid them at all costs.

Your safest choice is to buy your charger directly from the gadget manufacturer. You should also know the signs of a shady gadget charger.

3. You have to let your battery drain to zero before charging

Nickel-Cadmium batteries, which used to be a staple of home electronics, had a "memory effect." That meant if you didn't drain them fully before each charging, they'd eventually stop holding as much electricity.

The Lithium-ion batteries that have replaced them in modern gadgets don't have that problem. In fact, Li-ion batteries last longest when you keep them between 40 percent and 80 percent charged. Also, if you let Li-ion batteries discharge completely for too long, they can be permanently damaged or become dangerous as we explain here.

But Li-ions do have one challenge. The batteries have a built-in sensor that tells your gadget how much electricity is left in the battery. Over time, that stops matching up with the battery's actual charge. To reset it, you have to charge the Li-ion battery to full, let it run down to the point where your gadget gives you a serious battery warning and then charge it back up to full again. However, this only needs to be done every three months or so.

For some gadgets, you might not need to do it at all. Apple used to recommend this process but now says it is no longer needed. Check your gadget's manual to see if it has any specific directions.

4. Always shut down your computer at night

This myth goes all the way back to the early days of computers. Back then, computer parts, especially hard drives, wore out much faster than they do today. So, the idea was that to make your computer last longer, you should always shut it down at night. Some people still cling to that concept, and there is a little grain of truth in it.

However, modern computers have more-robust parts, which means you can let them run with little to no problem. Whether you shut down your computer nightly now just comes down to personal preference. If you want your computer to do things like back up, update or other intensive tasks, you can schedule them at night while you are not using your system.

If you're concerned about saving energy, turn it off. Or you can use one of your computer's many power-saving modes, which are faster for getting it going again in the morning.

5. You need to defragment your hard drive

This is a myth that used to be true, but no longer is. Given the way conventional magnetic hard drives read and write data, over time bits of data that should be next to each other get jumbled. So, to pull up a file, the drive would have to travel to 15 different places instead of 1 or 2, which slows down your system.

It used to be that you'd occasionally need to manually run a utility to defrag your system. Now, that function is built into Windows and other major operating systems, and it's run it automatically as needed. There's no need for you to do a thing.

In fact, defragmenting can even cause a problem if you're using a solid-state hard drive. Not only do SSDs not have fragmentation problems, the memory cells are only good for a certain number of reads and writes. Running a defragmenting program just wears out your drive faster.

6. You can completely wipe data

Hopefully, you know that when you delete a file from your computer it isn't gone for good. It's still hanging around on your hard drive waiting for another file to overwrite it. Until that happens, you can recover it.

That's a problem if you're selling or giving away a computer; you never know what information a computer-savvy person can pull from the system. You need to make sure the data is gone for good, but how?

In the olden days of magnetic media with early hard drives and floppy disks, waving a magnet over the drive or disk would do the job. However, modern hard drives are much more resistant to magnetism, so that won't work.

The generally accepted way to wipe your information is with a program that overwrites your hard drive with random data several times. That way, there isn't anything to recover. Learn the detailed steps to wipe your computer or mobile gadget here.

That's fine for conventional drives, but because of the way solid-state drives work, both in computers and mobile gadgets, you can never be sure you've gotten everything. Mobile gadgets do include a reset feature, and many SSDs come with their own wiping software. However, something might get missed.

In most cases, no one is going to go looking for what's been left behind, or get anything too important. However, if you're really worried, you can keep your gadgets at home and use them for other projects. You can also remove your hard drive from the computer before giving it away and store it, turn it into an external drive, destroy it, or make art with it.

Interesting fact: Since 2007, the federal government mandates that for hard drives and other media that have contained classified material, the only option is to completely wipe and then destroy them.

7. Private browsing is totally private

Every Web browser has a private mode. When private browsing mode is on, the browser won't record where you go and it wipes most of the information someone using the computer could use to piece together your online travels.

In Microsoft Edge, Internet Explorer, Firefox and Safari, you enter private browsing mode using the keyboard shortcut CTRL + SHIFT + P (CTRL + OPTION + P on Mac). In Chrome, you use CTRL + SHIFT + N (OPTION + SHIFT + N on Macs). Click here to learn more about private browsing and how you know you're in private browsing mode.

What you might not know is that private browsing isn’t foolproof. It doesn't hide your browsing from your Internet service provider, the sites you visit or any law enforcement that happens to be watching. Ditto if there’s a logger on the computer or the router is set to record sites visited. Like most things in tech, private only means that it’s harder to find.

Bonus: More is always better

This is a general myth that tech manufacturers love because it boosts sales. However, it isn't always true, and sometimes more can even hurt you.

You might be deciding between a laptop with a 256 gigabyte solid-state hard drive and a 1 terabyte conventional hard drive. A 1TB drive is four times larger, but an SSD is much faster and more reliable. Plus, most people rarely even fill up a 256GB hard drive.

Similarly, you shouldn't automatically buy the camera with more megapixels or the smartphone with the highest-resolution screen. In a camera, image quality is as much about the size of the image sensor as the number of megapixels.

With smartphone screens, after a certain point you can't tell the difference in resolution (and most high-end and mid-range smartphones are past that point). However, a higher-resolution screen burns battery life faster.