Make a Resolution
The number of pixels that form the picture on a TV horizontally and vertically is known as resolution. The more pixels on display, the sharper the image becomes, which is why higher-definition televisions have come to dominate the market. With 4K resolution, ultra HD sets are also becoming more popular and affordable, providing images with rich, vivid detail. However, the difference between 1080p HD and 4K can be subtle and less noticeable from a distance and more pronounced when you get up close and personal.
One important thing to keep in mind is that not all content is available in 4K—like live television—therefore, you'll want to be sure that you can take advantage of your new shiny resolution. Many of the apps for the latest streaming services come pre-installed or can be easily downloaded to most Smart TVs. Popular streaming devices—like Apple TV 4K, Fire TV Stick 4K, Roku, and Chromecast with Google TV—also offer the ability to stream 4K content, and are often faster and offer more features than the ones built into your television.
Although 8K televisions have recently become available, you are fine avoiding them for now. The price is substantially higher, and there is no 8K content or services available yet. By the time there is, the technology will have improved (and likely become cheaper), making your "first adopter" purchase outdated and obsolete.
4K televisions also offer HDR, or High Dynamic Range, which produces more vivid colors, higher contrast, and greater brightness. There are currently five different HDR formats, but Dolby Vision is becoming the de facto HDR standard, with more and more streaming services offering the superior form of HDR. TV manufacturers like LG, Sony, Philips, and Panasonic offer the biggest selection of hardware that displays Dolby Vision, provided it's offered for the content you're watching; otherwise, it will display in the highest HDR format available.