Whether you're looking to buy a smartphone outright or commit to a pay-monthly contract, the sheer number of handsets can be bewildering. Don't be limited by what's on offer by your current mobile provider, though, as it's fairly painless to switch to another and take your number with you.
The first thing to consider is what you will use your smartphone for. For most people, the answer is calls, texts, email and web browsing. Any smartphone will allow you to do these things, but if you'll be sending lots of texts and emails, you may prefer a hardware keyboard rather than an on-screen model. BlackBerrys aren't the only smartphones with physical keys, but you might be surprised how quick and easy it is to type on a virtual touchscreen keyboard.
Apps are the other major consideration, as third-party programs vastly expand the capabilities of your smartphone. Apple's App Store and Google's Android Market have hundreds of thousands of apps to choose between, covering just about every possible task from finding train times to organising recipes. If you're also thinking of buying a tablet, it's worth choosing the same platform as many apps you buy will work on both devices.
There are four main choices: Apple iOS, Google Android, BlackBerry OS and Windows Phone. Apple and RIM don't licence their mobile operating systems to other manufacturers, so your choice of handset is limited to the firms' own ranges. Google and Microsoft let a variety of manufacturers use their operating systems, so the choice is wider.
Apple's iOS is a slick-looking, easy-to-use interface but you're tied to iTunes to load content onto your phone. It's a similar situation with Windows Phone devices: you have to install and use Microsoft's Zune software.
With Android handsets, you can drag and drop files just as you would with a USB flash drive, making them much more flexible. This open design has disadvantages, though. It's possible that the handset won't be able to view or play the files you've uploaded – they may use a codec that isn't supported, for example. Although you're much more locked down with iOS and Windows Phone, you can be pretty sure that everything will work.
It's a similar story with apps. Apple and Microsoft vet the apps in their app stores, but Google doesn't. There's no guarantee of quality with Android apps, or that they're free from malware.
It's worth popping in to your local phone store to try out each of the operating systems to find out which one you like best.
When it comes to storage, think big. Even if you're not planning to keep a large music library on your phone or watch a lot of videos, it's worth having lots of space for apps. This is especially important on handsets such as the iPhone which can't be expanded with memory cards. Consider 16GB as a sensible minimum.
Capacity isn't such an issue if you choose a handset with a MicroSD Card slot or if you're likely to stream music using a service such as Spotify.
Smartphones are personal devices, and some people prefer a tiny phone that will fit easily in a pocket while others would rather have a big screen that's good for watching movies. Screen sizes range from around 3in to over 5in, but the largest phones can be quite bulky. Conversely, smaller screens may not have enough room to display a Qwerty keyboard when upright and the resulting combined keys are much more cumbersome to use.
Screen resolution also varies widely. Some smartphones have screens with 320x480 pixels, and this appears much blockier than the ‘quarter HD' screens which have a 540x960 resolution. More pixels mean that text and photos look sharper, and more information can be shown on screen at once.
The iPhone has been widely criticised for not supporting Flash, but this is now far less of a problem as dedicated apps allow you to use many websites (such as YouTube) that ordinarily rely on the technology for videos and other content.
Flash is slowly being replaced by HTML5, but if you need to use a website that still uses it, you'll want a smartphone that supports it. Android does, but look for a powerful processor – at least 1GHz – as Flash demands plenty of grunt.
Games can also be power hungry, so a fast processor and graphics chip are things to look for if you want to play games such as racing simulators and first-person-shooters. In general, a dual- or even quad-core processor is worth having over a single-core CPU as it makes the smartphone more responsive when running multiple apps.
Data security might be important to you, particularly if want to buy anything or store personal information on your phone. All smartphones have security in one form or another, with most providing PIN-protection when the handset is turned on. On Android smartphones, a swipe pattern to unlock the device is common.
The apps you install and the social networks you use also pose security risks. Apps such as Lookout can help check the integrity of items you attempt to download, but location-tracking apps and messaging apps can also be problematic in their own way. iPhone and BlackBerry handsets are more secure than the open-source Google Android platform, but you should still practice caution.
BlackBerry and iPhone smartphones can be remotely tracked – handy if you lose your phone – and can also be remotely wiped, so if a thief steals it, you can delete the contents.
Price is arguably the main factor for a lot of people, but the price of the smartphone is usually worked into the monthly contract price. For example, it's common to see even expensive handsets offered free if you sign up for an 18- or 24-month contract at £30 per month. The amount of included call time, text messages and data (for internet and downloads) varies, so it pays to compare tariffs carefully.
Calculate the total price you'll pay over the duration of the contract, as it might work out cheaper to buy the handset outright and opt for a SIM-only contract, or a pay-as-you-go deal. If you buy a smartphone outright, it will be unlocked which means it will work on any mobile network.
Handsets that are bought on a contract are likely to be locked to the network you signed up with. You may have to pay to have it unlocked to switch to another provider.
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