The pace of innovation in the smartphone world is moving so fast it's almost scary. Screens seem to be growing by the minute; processors have gone quad-core (and even octa-core), and a growing number of phones double as TV remotes. That's why you need to choose wisely when shopping for a handset. The last thing you want is a phone that looks dated a few months after you take it home, especially since most people still sign up for two-year contracts.

Want to avoid smartphone remorse? Follow these seven tips.

1. Pick your carrier

Verizon and AT&T continue to lead the pack when it comes to 4G LTE coverage, with the former carrier covering more than 486 markets and the latter blanketing 161 and counting. Meanwhile, Sprint comes in third with 67 markets and counting, while T-Mobile is just getting off the ground with 7 cities. Not surprisingly, Verizon and AT&T also offer the widest variety of handsets to go along with their superior coverage.

But you'll pay more for this superiority. Verizon charges $100 per month for 2GB of data and unlimited talk and text, while AT&T asks for $110 per month for 4GB of data and unlimited talk and text. The good news is that these shared data plans include mobile hotspot usage. Those who don't need unlimited minutes on AT&T can spend $90 per month to get 550 minutes and 3GB of data.

However, coverage is only one part of the equation. Unlike AT&T and Verizon, Sprint and T-Mobile both offer unlimited data. Sprint customers who opt for 450 minutes can get unlimited data for $79.99 per month. T-Mobile has the cheapest plans of the big four, offering unlimited voice, text and data for $70 per month. Plus, T-Mobile's payment plans allow users to fork over less money up front for the phone. However, Sprint charges $19 extra per month for mobile hotspot, while T-Mobile customers who sign up for the unlimited data plan will pay $10 for 2GB.

Those looking to save even more money can opt for a smaller carrier such as MetroPCS (set to merge with T-Mobile), which provides unlimited data for $60 per month. Virgin Mobile costs an even cheaper $55 per month.

Bottom line: It really comes down to how much you're willing to spend per month. T-Mobile offers the sweetest deal, but its 4G LTE network is just rolling out. And while Sprint also provides unlimited data, its network is also still fairly skimpy. AT&T and Verizon charge more, but if you can afford them, you'll get better coverage.

2. Choose your OS

The operating system and software a smartphone uses are paramount, because they define the user experience. The OS also dictates the amount and quality of apps available. Here's a breakdown:

Android mascotAndroid

Google's Android operating system has become the world's most dominant platform, and for good reason. Several smartphone makers have adopted Google's platform and now offer a wide variety of devices in multiple sizes and at multiple price points. But choice isn't the only reason Android is in the lead. Its OS is more customizable than iOS (for both users and manufacturers), and the Google Play store stocks just about as many apps as does Apple's App Store, at more than 700,000 titles.

The latest version of Android, Jelly Bean, delivers such welcome upgrades as offline voice typing and Google Now, which learns from your searches to anticipate your needs. Meanwhile, Android partners like Samsung, HTC and LG are adding value to Google's software with tons of useful features, from camera and multitasking enhancements to apps that turn your phone into a TV remote control.

Android's biggest weakness is how long it takes carriers and phone makers to update to the latest version of the OS. Malware has been another issue.

The backside of an iPhone 4Apple iOS 6

There are two reasons Apple's iOS is still so appealing: simplicity and apps. The iconic grid of icons is so easy to use anyone can pick up an iPhone and start using it. At the same time, Apple has layered features on top of its software to make it robust without being intimidating. Most importantly, Apple offers more than 775,000 apps, and the company routinely gets the most cutting edge apps first (see Flipboard, Infinity Blade, Vine, Mailbox, etc.)

And iOS 6 delivers other welcome improvements, such as Facebook integration, Passbook (which aggregates coupons, tickets and more in one place) and Shared Photo Streams. The Maps app has steadily improved, but it still trails Google Maps. Siri is always just a long press of the home button away, ready to answer all sorts of questions, book a restaurant or tell you who won last night's game.

While we like iOS, it offers a less dynamic look and feel than the Windows Phone, and Android overlays like Samsung provide much quicker access to important settings. Fortunately, when Apple does decide to give its software a fresh coat of paint, you won't have to wait an eternity for it. Owners of the iPhone can download updates directly from Apple without dealing with a carrier middleman. [10 Ways the iPhone 5 Beats Android]

BlackBerry z10BlackBerry 10

The new BlackBerry OS is tailor-made for multitasking on the move. Just swipe up from the bottom of the screen at any time to see all of your open apps. Another highlight is BlackBerry Hub, which aggregates everything from email and BBM to Facebook and Twitter. Last but not least, a redesigned keyboard predicts words and lets you flick up on suggestions to speed up typing.

The associated app store, BlackBerry World, is off to a strong start, surpassing 100,000 apps shortly after launch. You'll find a wide selection of popular titles, from "Angry Birds Star Wars" and The Weather Channel to Kindle and Slacker. BlackBerry World also includes a lot of apps that have been ported over from Android, but it's still missing key apps like Pandora, Netflix and Instagram.

In another drawback, the BlackBerry 10's phone specs lag a generation behind the latest Android handsets, both in terms of screen size and processors.

A Samsung phone with the Windows 8 mobile OSWindows Phone 8

A great choice for first-time smartphone owners and parents, Windows Phone 8 offers a dynamic and user-friendly Live Tile interface that delivers updates right to your phone's Start screen. You can pin a whole lot of stuff to this screen to help save time, from your favorite people and websites to important notes and music playlists. Kids' Corner gives parents an easy way to keep their children away from adult content.

On the other hand, Windows Phones tend to trail Android handsets when it comes to cutting edge specs. And while the Windows Phone app store is growing (more than 135,000 options) and recently added Pandora, it's still missing the likes of Instagram, Flipboard and Temple Run 2.

Bottom line: Get iOS if you prioritize ease of use and apps, Android if you crave customization and more features, BlackBerry for better productivity and Windows Phone for an experience that's more fun and personal.

3. Get the right screen size

LAPTOP comparison of smartphone screen sizes

Smartphone screens keep getting bigger, but what's the right size for you? At this point, we would avoid anything smaller than 4 inches. Devices like the 4-inch iPhone 5 and 4.2-inch BlackBerry Z10 are one-hand friendly while providing plenty of real estate for enjoying apps. At the other end of the size continuum are so-called phablets like the Samsung Galaxy Note II with its 5.5-inch screen. It's more of a two-hand experience, as evidenced by the pen support. But some people find that extra real estate so useful (for Web surfing, watching video, etc.) that they don't even have a need for a tablet.

The new sweet spot for smartphones is quickly becoming the 4.5 to 5-inch range, which is where you'll find such handsets as the Samsung Galaxy S4 and HTC One. You have to stretch your thumb a bit to reach all four corners of the screen, but these phones nicely balance portability with the extra size users crave for gaming, watching movies and even just typing on a larger keyboard.

Bottom line: Screen size is very subjective, so put that smartphone in your hands before you buy, to make sure both your eyes and your fingers will be happy.

4. Know what specs you need

Consumers care more about the user experience and what a phone can do for them than what kind of processor it has, but that doesn't mean the specs aren't important. For example, a cutting edge, quad-core Qualcomm Snapdragon 600 processor will give you a lot more speed for gaming, multitasking and more than would a dual-core chip. Nvidia's Tegra 4 processor also promises blazing performance, but it hasn't yet reached phones.

In terms of memory, 2GB of RAM has become standard on higher-end phones, as has 16GB of storage. If you care about expandability, opt for a handset with a microSD card slot. If you plan on shooting a lot of HD video or downloading a lot of 3D games and movies, spend the extra money to get 32GB, especially if that phone doesn't have a card slot.

So what about the camera? Don't be fooled by high-megapixel claims. While a 12-MP camera should give you more detail than a 5-MP model, ultimately the size of the sensor and quality of the lens will play a bigger role in determining how great those photos look. The HTC One, for example, shoots only 4-MP images but captures 300 percent more light than competing phones, giving you brighter photos. Also, pay attention to special features. For instance, the Galaxy S4 can shoot using both the front and back camera at the same time.

Bottom line: Android phones tend to have the most cutting edge specs, followed by the iPhone. Windows Phones and BlackBerry 10 are about a generation behind.

Charging a cellphone's battery5. Pay attention to battery life

What good is a high-powered smartphone that runs out of power by lunchtime? Based on the LAPTOP Battery Test, which involves continuous 4G Web surfing on 40 percent brightness, the average phone lasts 6:06. That's good, but we've seen several handsets last 7.5 hours or longer. For example, the Motorola Droid RAZR Maxx HD, which has a massive 3,300 mAh battery, lasted 8 hours and 13 minutes on our test. The Galaxy Note II, which benefits from a 3,100 mAH battery, lasted a whopping 10 hours and 12 minutes.

The size of the battery isn't everything, though. Keep an eye out for special power-saving features that manufacturers may include. For example, Motorola's Smart Actions app can extend your endurance by recognizing when your phone is idle and conserving power during those down times. Samsung's Galaxy line also has a Power-Saving mode. If you want the ability to swap out batteries, make sure the phone you buy has a removable back cover and battery, as opposed to a sealed design.

Bottom line: Take a look at the mAh rating for the battery, but the most important thing to do is look at our battery life scores.

6. Get the best special features

In the new smartphone arms race, designers want to deliver special features that let you do things with your phone you couldn't before. For example, the Samsung Galaxy S4, LG Optimus G Pro and HTC One can all be used as TV remotes, because they integrate an IR blaster and a dedicated app. Samsung goes the extra mile with the Galaxy S4, offering new Air Gestures, health and translation apps, and the ability to broadcast the same song to multiple S4s simultaneously.

Meanwhile, the iPhone has the Siri personal assistant, Shared Photo Streams and FaceTime, Apple's own video chat service. Windows Phone fan? Only Nokia offers a PureView camera, which delivers unparalleled low-light performance, and the augmented reality City Lens app. HTC touts Beats Audio for both its Android and Windows phones.

Bottom line: Do your homework to learn the difference between features you'll find useful and those you'll ignore after a few days.

7. Don't be afraid to splurge

LAPTOP breakdown of Verizon's data plan cost

If you add up how much you'll pay for your plan over two years, it just makes sense to get the very best device you can afford, especially if you'll be on a contract. Let's say you signed up for a 2GB plan on Verizon. After 24 months, you would have spent $2,599, including the cost of a $199 phone, versus $2,499 if you purchased a $99 phone. To us, it's worth the extra money to get the latest and greatest phone.

However, if you simply don't have $199 or more to spend up front, you have some options. T-Mobile lets you grab a premium device like the iPhone 5 for just $99 down. Or you could shop around on Amazon or other sites for a feature-rich phone that has been discounted. If you're more comfortable going through your carrier, consider a device that's been refurbished or an attractive phone that's been discounted. For instance, you can now grab the Motorola Droid RAZR M for free on Verizon.

Bottom line: Spend more up front if you can to stave off obsolescence.

Photos and charts: .RGB./Flickr; Sean Davis/Flickr; Halal Bilal/Flickr; vernieman/Flickr; LAPTOP; brendan-c/Flickr; LAPTOP

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This story was originally written for LAPTOP and was republished with permission here. Copyright 2013 LAPTOP, a TechMediaNetwork company.
Everything you need to know about buying a smartphone
Want to avoid smartphone remorse? Follow these seven tips.