Smartphone screens make or break your experience. It is also the second most expensive element of the phone to replace. If you value your device, apply a screen protector to stop scratches and other damage.

What you might have trouble with is choosing which screen protector to use. There is a wide variety of them online, ranging from about $2 to $50. Jargon like "9H hardness" and "tempered glass" will throw you off more. So what should you buy? Here's a quick guide to understanding screen protectors.

1. Do You Need a Screen Protector?

You've seen the ads for Gorilla Glass screens on your phone. So does your smartphone still need a screen protector? Yes, it does, if you are willing to buy a good protector.

Most smartphones today boast Gorilla Glass, Dragontrail, or other scratch-resistant glass. This type of glass is resistant to scratches and cracks, but it's not foolproof. Certain objects like beach sand can quickly damage your screen nonetheless. And unless you have a DIY fix-able phone like Fairphone, you'll be spending a big amount.

Screen protectors are just as vulnerable to such scratches and cracks. But they act as an added layer of security, which is sometimes all you need.

2. Plastic vs. Tempered Glass

Mostly, you will find two types of screen protectors: plastic film and tempered glass.

Plastic film protectors have been around for a long time now, and you've probably seen these or applied them on your phone. They look like a little sheet of plastic. You need to stick them carefully, as they roll up easily.

Plastic protectors are quite cheap, aren't too sturdy, and don't help in case of falls and drops. They are decent for regular scratches, but tempered glass is more resilient. Plastic screen protectors come in two kinds: wet-apply and dry-apply. Wet-apply offers more resilience but can look pitted, like an orange peel, after a while.

Tempered glass protectors have become more popular in the last couple of years, especially with a big price drop. You can now find them for as low as $5, which is a small investment to protect a phone worth hundreds of dollars.

Tempered glass protectors offer better resistance against scratches, and more importantly, insulates your screen a bit against drops. Tempered glass also more closely mimics the feel of your actual screen, which makes it much more pleasant to use.

Related: Important Reasons You Should Put a Screen Protector on Your Smartphone

Of the two, it makes more sense to buy a tempered glass protector today. You'll be spending only a couple of bucks more to get much more protection.

3. What Is a Tempered Glass Protector?

Tempered glass protectors, as the name suggests, are made from glass. Tempering is the process of heating the glass to form a sheet and then rapidly cooling it. The result is a piece of glass that is a bit more durable.

The tell-tale sign of a tempered glass protector is that it's hard and holds its shape. Its stiffness makes it easier to apply since you can carefully align it and then stick it on. On top of that, it's far easier to pull off a tempered glass screen protector than to replace a damaged phone display.

4. Can Tempered Glass Protectors Bend?

Hold one in your hand, and you will feel it bend a little. Your mind races to ask, "Wait a minute, if this is glass, how come it's flexible?"

Newsflash: glass can bend.

Want to know something shocking? The screen on your iPhone, your iPad, your Android, your Nintendo Switch can all bend.

Of course, you absolutely should not try that at home. In fact, there are practical things to do if you break your screen.

Don't think of these pieces of glass the way you think of the glasses in your kitchen or your coffee table. Those are much thicker than what you have here. The thinness and the tempering process make this glass tougher, which is why it can take a little more pressure before cracking.

5. What Is 9H Hardness? What Really Matters?

Once you start shopping for glass screen protectors online, you'll see a few specifications pop up. Things like 9H hardness, military-grade protection, oleophobic nano-coating, and so on. Here's a quick rundown of what they mean and what really matters.

Related: Hard vs. Soft Phone Cases: Which Protects Your Phone Better?

9H Hardness

Contrary to popular opinion, this isn't a measure of the Mohs Hardness Test.

9H Hardness refers to the screen not getting scratched by a 9H pencil, the toughest of all standard pencils. It's not a great test, to be honest, but it's a decent parameter to determine if the manufacturer cares enough to test the protector.

Oleophobic Nano-coating

This is the only specification that you should look for. Unlike plastic film protectors, tempered glass retains fingerprint smudges. An oleophobic coating repels oil, which basically means your fingerprints won't stick on. A swipe with a micro-fiber cloth will get rid of them.

Military Grade Protection

You'll find this touted often, but it's a gimmick. The screen protector's toughness won't always stop your screen from cracking upon the impact of a fall.

Privacy Layer

Apparently, reducing the viewing angles of a screen is now a "feature" since people next to you can't read it. Don't fall for this one, folks.

Matte Display

Ah, the good old matte vs. glossy display argument. Depending on what kind of screen you prefer, pick the protector. Matte protectors aren't as common as glossy ones, but they are available for most popular handsets.

The bottom line is that picking the right protector can be a long quest, but it's worth it once you find the right one.

6. The Reality of Screen Protectors

Remember, protectors sit on top of the screen, even if it's an edge-to-edge protector. They don't surround the whole phone as a case does. So if your phone falls onto a corner, the screen and the protector will both crack from there.

The four corners of your phone are the most vulnerable parts of your device. Just because the screen protector isn't hurt by that fall doesn't mean the actual screen won't. The actual screen is held together by your phone's body. When that takes an impact, so does the screen.

Protectors help protect against everyday scratches and face-down falls. A tempered glass protector will crack before your actual screen cracks—if the face hits the ground first. More importantly, that $5 piece of glass will keep the screen safe from the keys in your pocket or other such accidental scratches.

Which is Better: 9D or 9H Tempered Glass?

Contrary to what many people expect, the "9D vs. 9H tempered glass" question is inaccurate, as tempered glass can be 9D and 9H simultaneously.

A number followed by "D" for dimension, whether it's 9 or 21, speaks to the curved nature of the tempered glass. While the "H" refers to the screen not being scratched by a 9h pencil. So there's really no comparison between 9D and 9H tempered glass.

Do You Use a Screen Protector?

Gorilla Glass is a tough layer to protect the screen of your smartphone already. For some people, that's more than enough safety. A protector is never as comfortable as using the naked screen of your phone, and it doesn't always sit flush with the body either. Aesthetically, it's a problem.

Image Credits: Perfect Vectors/Shutterstock