The TV has come a long way. Tube TVs that weigh as much as a truck and wonky rabbit-ear antennas seem like a bad dream these days, and amenities like built-in WiFi and streaming apps that were once only found on the best TVs are now more or less standard.

But all those innovations raise lots of questions when shopping for a new TV. How big should mine be? What does 1080p actually mean? Do I need 3D? What's the best TV for watching sports? And what about cost? Nobody wants a cheap TV, but as prices drop as new models hit the shelves, what is the threshold for cheap TVs and what's just a plain old good deal? With this TV buying guide, you won't be daunted when it's time to make a decision on the new centerpiece of your home-entertainment setup.

How big should my screen be?

Well, that depends on a few things, including but not limited to how big your living room is and how far away you'll be seated from the screen. First off, you should keep in mind that the number in inches that's attached to a TV's description is its corner-to-corner measurement. While this is one of the chief ways manufacturers and stores sort TVs, it's not the only number that counts. Make sure you take width, height, depth, and other dimensions—such as wall-mount measurements—into account when picking yours. Lots of TV sizes are listed by "class." A 32" class TV, for example, might actually only have a screen that measures 31.5" diagonally. The difference usually isn't big enough to change the viewing experience.

Tip: To find the perfect TV size for your space, calculate the distance you'll be sitting from the screen in inches and divide by two.

How do I know what resolution I should get?

You're likely to see one of three resolutions when shopping around for an HDTV: 720p, 1080p, or 4K/UHD. That sounds more overwhelming than it is. In the simplest terms, the bigger the number, the better the resolution. But the truth is that your real choice is likely between 1080p and 4K, as the price difference between 720p and 1080p is now so narrow that it almost always makes sense to default to the higher resolution. The below table briefly explains each resolution standard's characteristics:

Okay, but what about the type of screen?

A TV's screen requires a lighting source to generate its picture. Currently, two of the more popular screen-lighting technologies are LED and OLED. Basically, an OLED will cost a not-insignificant amount more, but it'll have the quality to back up the price tag. OLED screens feature true-black tones, less motion blur, and highly accurate color representation. That said, LED screens still provide a quality viewing experience and you'd be unlikely to notice the difference between LED and OLED screens unless you put the two side by side.

Are 3D or curved screens automatically the best TVs?

Not necessarily! Curved TVs can make the viewing experience feel more immersive, but they don't offer the best view if you have to crowd around the edges of the TV. As for 3D TVs, it simply depends on how much you enjoy 3D content. If that's important to you, then it's well worth it, otherwise it's just a fun feature that can be tacked onto a great TV for extra oomph (and a little extra dough).

What are refresh rates?

Ahh, yes, refresh rates—or as Samsung calls them, "Clear Motion Rates"—are pretty confusing to the layperson. Put simply, a TV's refresh rate is a measure of how quickly the screen regenerates its images. Think of it like a futuristic flip book; the slower you flip (lower refresh rate), the choppier the movement is. Speed through it (higher refresh rate), and you start to see a smoother, more realistic moving image. If you're concerned about it, make sure you investigate the specs to find the actual refresh rate (Samsung's CMR isn't quite the same thing) or head to a store to see the differences for yourself.

Tip: 60Hz is the standard refresh rate for most movies and shows on TV, 120Hz or so is what you'll want for that smoothing effect.

Wait, why do I even care about the refresh rate?

Good question! Refresh rate probably matters the most to sports fanatics. The smooth look makes it easier to pick out players on the court, follow a puck that flies across the ice, and take in the wonder of a baseball player swinging a bat. That said, almost all TV shows and movies weren't made to have an adjusted frame rate, so unless you have a lot of trouble following quick action sequences, you probably don't need to have it on. Ever watched a favorite movie on a new TV and feel like everything suddenly looks a bit like a 1980s soap opera? That's the smooth motion in action. Luckily, you can just switch it off in the TV's menu when you don't need it.

Should I get a smart TV or a Roku?

Luckily, this isn't much of concern anymore as almost all TVs being sold—even relatively cheap TVs—have some smart functionality. That means there's a good chance your new set will already have built-in WiFi, a series of apps such as YouTube and Netflix, and full-fledged browsers for surfing the web. You can even download additional apps, like MLB.tv and PlayStation Now.

That said, there are certain apps that can't be downloaded onto just any TV. HBO Now, for instance, only partners with select brands and devices. That means if you want to keep up with Game of Thrones but you have a Vizio TV instead of one of the app's approved brands, you'll need a Roku, Amazon Fire Stick, or Chromecast or another streaming media device.