The iPhone is by far the best-selling mobile device on the market. But it does come with a hefty price tag. Sure, an iPhone is cool; it's also pretty fast, reliable and gets great service. But that doesn't necessarily mean that you need an upgrade. With Apple tending to keep to a once yearly up date of the iPhone, the differences between models can be small, and may not be worth the price if you're on a budget. Today we're looking at upgrading to the iPhone 5, is it worth it? Depending on your needs, your budgets, and your current phone model, you might want to go new, or to hang on to what you have. Read on to find out the advantages and disadvantages to switching to the new model...

Why You Might Want to Upgrade to the iPhone 5...

There are obviously some new features that might make an upgrade desirable. Probably the biggest difference between the new iPhone ad previous models is that we finally get a bigger screen. The four inch screen on the new model (as compared to the three and a half inch screen on previous models) means that you get a more comfortable viewing experience, whether that's for web browsing, email reading or video watching. In fact, a key difference in the new screen is that it's a more traditional 16:9 ratio (as opposed to the older 3:2 ratio), so it's easier to watch videos without getting the letter box effect.

Theoretically, the new iPhone is also faster, coming with an A6 processor, rather than the A5 processor on the older model. This should make processing twice as fast, although the difference isn't always very noticeable in everyday use. For some people, the ability to connect over 4G is a big advantage to the new iPhone. 4G isn't available everywhere, or with all mobile service providers, but where it is available you get faster mobile internet speeds.

You also get better battery life on the new iPhone, with Apple claiming that you get an extra hour of web surfing, an extra two hours of 3G use and a huge extra twenty five hours of standby time on the new battery. For big users, this extra battery life might be worth the cost.

Plus, the new iPhone is thinner and lighter than older models, despite having a larger screen. It's around eighteen per cent thinner, and twenty per cent lighter than the last model, making it that much easier to carry around with you.

Finally, though the cost may be an issue for some people, it's worth remembering that you can trade in an older model for a newer one. An iPhone 4S in good condition is liable to get you around £200 knocked off the price of a new model, so it's something to consider doing if you do want that upgrade.

Reasons Not to Get the Upgrade...

Having said all that though, there are also quite a few reasons why you might not want to upgrade to the iPhone 5.

Firstly, the new operating system, iOS6, with all its new features will be available on the iPhone 4S. So if you're looking for panoramic photos or an enhanced Siri, then you don't need a new iPhone to get them. Though it's worth noting that a lot of the new operating system's features won't work on the iPhone 4 and below.

4G might be a great reason to upgrade if you want a faster internet connection, but if it's not available in your area, or through your mobile service provider, then the upgrade might not be worth it to you. You should definitely check out 4G availability before making the decision to buy.

And that extra processing power might seem nice, but as we mentioned above, during every day, average phone use, the speed difference really isn't noticeable at all.

Then there's the question of compatibility. The new model iPhone uses a lightning connector, rather than the traditional iPhone connector, so many accessories from docking stations to charging cables simply aren't compatible with the new iPhone, and the difference in size means that things like screen protectors, covers and cases are also incompatible.

You'll also be required to run iTunes 10.7 in order to update and back up your iPhone, and if you own an older computer this just might not be possible. You'll need to run minimum OS X 10.6 Snow Leopard on your home computer to be able to use iTunes 10.7.

Plus, there are a few important things that aren't any different on the new model iPhone. The camera and the storage capacity of both the 5 and the 4S are exactly the same, with no noticeable differences at all. Finally, there is that price tag. Yes, you might be able to get some cash by selling an older model iPhone, but there's still a lot of extra cash to pay up front for a new model. And if you're on a mobile phone contract, and right in the middle of that contract, you're going to have to pay the full up front price for a new model iPhone.

On top of that, you might even end up still paying in instalments for your old phone on top of your phone bill, meaning that you're basically paying for two phones at the same time.

Should I Get the Upgrade?

If the new iPhone has features that you're desperately looking for, then maybe it's worth it to you to get the upgrade. On the same note, if you're currently running an iPhone 4, iPhone 3S or iPhone 2, yes, the upgrade is probably worth it. The extra power and features that you'll get will mean that you have a far better phone experience.

However, if you're currently using an iPhone 4S, there's probably not enough difference in the new model to make the price worthwhile. Whilst there are a few neat tricks to the new model, the iPhone 4S is still a great phone. And since both devices will run the same operating system, an upgrade is probably not worth your time or money.