1. Closing apps will speed up your iPhone. Hmm – we know you can remove them from the task list to "refresh" them but does closing them all the time help? The truth is, they aren't running in the background, however, they are still in RAM. Apple limits what apps can do in the background, and what's more, they automatically will close apps not in use if it needs more RAM. By continually closing them, you will actually make them run slower since the RAM has to load all over again.
2. Using a task killer will speed up your Android phone. You shouldn't have to close an app on Android unless it starts giving you trouble and has issues. The same as above for iPhone, the apps are using RAM with limited background usage.
3. You should drain your battery fully before recharging it. Most people don't let their phones drain completely but what about "topping it off?" Modern Lithium-ion batteries can be plugged in and charged whenever you want, as much as you want.
4. You should only use the charger that comes with your device. Most devices and smartphones use a USB charger. As long as it can be plugged into a USB port, you should be able to use it. If you use a more powerful charger, your phone will still only pull what it needs. It may even charge faster. Likewise, a less powerful charger will charge slower or maybe not at all.
5. You should buy a screen protector to protect against scratches. This is that thin piece of film they sell you or charge to install for you to "prevent" scratches. Most modern phones are using Gorilla Glass, scratch resistant glass, or similar technology. If you aren't too rough you should be fine. There are also some things that would scratch a screen protector that won't harm the glass.
6. More megapixels mean a better camera. This is a myth for any digital device, cameras included. A high number that may look good on a spec sheet doesn't really translate to better. It's just squishing more megapixels in the same space. A megapixel is one million pixels. So if you have an 8-megapixel camera, it will have 8 million pixels. The 8 compared to the 16-megapixels will allow more light since they are bigger pixels. Take into consideration the sensor and image-processor as well.
7. Android phones often get viruses and malware. Technically a virus is self-replicating software. Phones do not get them and even if you get infected by malware, it won't infect other people's phones. Malware does exist but it tends to come from downloads outside of Google Play. If you download pirated apps, you could very easily be picking up malware. Just don't add apps from unknown sources.