When should I upgrade my HDTV?

When should you upgrade your TV? Every year sees new models that are bigger, better, with more features and lower pries. When is that point were the performance difference of a new TV is worth the hassle and the cost?

To find out, we have to take a look at how much better the current models are compare to what you have.

So let's take a look.

Picture quality
Whether current HDTVs look better than yours is, as you'd expect, largely related to how old your TV is. There's no solid answer, but I can give you some tips and tricks to track down how much better (if at all) new TVs are. As a general rule, if you bought a decent TV in the last few years, the new models will only look a little better. More than five years, and it gets harder to say.

Your best bet is to compare, if possible, the contrast ratio of your current TV with a new model. This is not to say you should compare what the company claims. As I detailed in my contrast ratio (or how every TV manufacturer lies to you) article, all contrast ratio specs are 100 percent fabrications. So you may need to do a bit of digging. Some Web sites, like CNET, measure the black level of TVs. This is a good start, as generally a lower black level is the first step toward a better contrast ratio. Each CNET review also compares TV's side by side, allowing for a visual comparison, which is great. Some other sites, like Sound and Vision Magazine, list measured contrast ratio for each review. Search for your TV, see how it performed, then search for the new model (presuming it's been reviewed already) and compare.

If you're going this route, I'd recommend sticking with one site for your numbers, as there's going to be enough measurer-to-measurer variation between reviewers to make cross-Web-site measurement comparisons dicey (sorry, so it goes). Even so, a difference of 20 to 30 percent in measured contrast ratio isn't likely to be noticeable, even side by side. A lot more than that? The TV probably looks a little better.

Generally speaking, with LED LCDs the better the local dimming, the better the apparent contrast. Check CNET's descriptions of the local dimming closely. If your TV doesn't have local dimming, and a new model does (and it works well) that TV probably looks better than yours (unless it's a recent plasma, in which case, maybe not). High Dynamic Range is a new feature worth looking our for as well.

Overall light output, at least as LCD and LED LCDs are concerned, have been well beyond what most people need for years. OLED, the models we've seen anyway, are also exceptionally bright.

But, as I said, name-brand TVs have looked pretty good for a bunch of years now. The rest of this list shows where the bigger differences are.

3D
If you've got a pre-3D HDTV, this is probably the most noticeable difference between yours and a new model. I say "probably" because... do you really want it? I'm biased, I don't really care about 3D. If you want to upgrade to 3D, there are a few things to keep in mind. The first is you'll also need a new Blu-ray player. Almost all of those are 3D-capable now, too, and are around $100, so that's easy.

The next is whether you want active or passive. Active 3D TVs use battery-powered shutter glasses. These are fairly expensive (though they're getting cheaper), and often rather heavy (though they're getting lighter). The benefit, though, is full 1080p resolution per eye.

The other method, used by some Toshiba, Vizio, and some LG models, is passive. These use cheap polarized glasses like you'd find in most movie theaters. They're light, pretty much eliminate crosstalk artifacts, and let more light pass through to your eye (so the image is brighter than with an active 3DTV). The downside is that because of the way it works, each eye only sees half the TV's total resolution. As in, you're only seeing 1,920x540 pixels per eye. If you sit close to the TV, or the TV is really big, you're going to see interlace lines, and jagged edges on diagonals.

Ultra HD 4K TVs with passive 3D deliver 3,840x1,080 per eye. So full Blu-ray resolution, and then some.

There are other pros and cons with each technology, enough to fill an entire article. Conveniently, I did just that: Active 3D vs. passive 3D: What's better?

Features/Internet streaming
Another big feature new in the last few years is built-in Internet streaming features, like Netflix, Vudu, Hulu Plus, and others. Some models even have built-in browsers so you can check e-mail and surf the Web. While these are all neat, I can't say that they're a good reason, in themselves, to upgrade. The Apple TV is a fantastic piece of kit, only $100, and streams Netflix and allows you to buy/rent TV shows and movies from iTunes. A lot of people like the Roku boxes for similar reasons.

Adding one of these to your system will give you the same general streaming features as those built into modern TVs. Perhaps not a Web browser, though. If you don't already use your phone or a tablet to surf the Web and check e-mail while you're watching TV, then a built-in Web browser is certainly cool.

Size
Tired of that tiny 42? How about an 85-inch?. Recently, we've seen a trend of dramatically increasing sizes and rapidly decreasing prices. Not only are screen sizes above 60 inches possible, but they've become fairly common and affordable. Sharp, for one, has 70- and even 80-inch models costing not much more than 60-inch LCDs from other brands. An enormous TV is awesome, though personally I think you shouldn't buy a jumbo LCD TV. Buy a projector instead. Check out my TV vs. projection article for more on that.

Or perhaps start from scratch, and check out How big a TV should I buy?

Green(-ish)
One last reason one might want to upgrade, is the better energy efficiency of newer televisions. While true, for the most part, this is somewhat misleading. Yes, modern televisions generally use less power than their predecessors, but upgrading with the idea of saving the environment is overly simplistic.

If you're going to use your old TV to replace an aging CRT in your bedroom or basement, then go for it. If you're just trying to "save money" on your electric bill, that's not going to happen. You'll never recoup the costs of a new TV in the money it saves you in electricity each month. Even the difference between the most power hungry plasma and most energy efficient LED LCD isn't enough to ever get the money back from the difference in price between them.

OLED and 4K
The two newest technologies in the TV world are OLED (an entirely new TV technology) and Ultra HD "4K" (a higher resolution).

OLED promises much better picture quality overall, including nearly infinite contrast ratios. Because it's so new, it's really expensive. Definitely worth checking out though, just to give you an idea where the future is headed. Here's a comparison with the current tech: LED LCD vs. OLED vs. plasma.

4K has four times the resolution of your current, 1080p, TV. However, resolution is only one aspect of picture quality, and not the most important (that would be contrast ratio). In smaller screen sizes, 4K TVs are stupid. In big screen sizes, like 85-inch TVs and projectors, 4K is awesome. Also, since there is very little content, and there's some concern over HDMI 2.0, I'd wait to get a 4K TV unless you really, really, really want one.

Bottom line

If you're just looking to get something new, or bigger, or just plain shinier, go for it. We've all been there. If you're torn, I'll sum up with this: unless you want 3D or new features, and your TV is only a few years old, stick with what you have. The new models probably aren't going to look that much better. If you've got an old plasma, or early LCD, then the new models probably will look a lot better. Need help decided between the different technologies? Check out LED LCD vs. plasma vs. LCD.

Have you upgraded recently? What did you upgrade from and to?

Got a question for Geoff? First, check out all the other articles he's written on topics like why all HDMI cables are the same, LED LCD vs. OLED, active versus passive 3D, and more. Still have a question?Send him an e-mail! He won't tell you what TV to buy, but he might use your letter in a future article. You can also send him a message on Twitter @TechWriterGeoff or Google+.