With Apple likely to release at least one new version of its phone on Tuesday, many iPhone users are going to wonder if now is the time to upgrade--or whether they should hold out for something better. And if you have a device that runs on Android or Windows Phone, you might be following the launch, too, to see if a switch is worth it. Either way, here are a couple questions you can already start asking yourself, before Apple unveils all the details.

How old is my phone now and how much longer can I stand it?  If you've had your phone for a couple years and it's a daily, tooth-grindingly annoying source of frustration, then you should definitely buy a new phone. It's an easier choice if your phone is due for an upgrade -- something that normally comes up every two years, unless you've opted for a plan that lets you upgrade your more frequently without penalty.

There were a lot of Apple fans who weren't impressed enough by the iPhone 5s and 5c to upgrade from the 4S, meaning that there are probably a lot of eager potential upgraders out there. And if you're still toting an iPhone 5, 4 or 4S, then you've got a pretty good incentive to upgrade now. Even if rumors of bigger screens don't pan out, there's a pretty good chance, based on Apple's past actions, that the new iPhone will have a next-generation processor in it -- one that will speed up your phone significantly.

If you have an iPhone 5s, it's a harder sell. If the reports about a bigger screen are true and you're suffering with the iPhone's current 4-inch screen, then you could probably justify the upgrade. But unless the small screen just drives you crazy, you should probably wait to see if there are any killer features announced Tuesday that make it worth your while. For 5c owners, the question really is whether you've been happy with Apple's cheaper, lower-tier smartphone to this point. If you've been okay , then you probably have no compelling reason to upgrade right now.

What do I need my phone to do? In a way, the next iPhone will be more about what services it offers--helping you open your garage door, tracking your exercise workouts--rather than the specifics of the hardware itself. Apple's aiming to create a sort of universal remote control for your life, and it's likely to rely on more user data than ever. Apple already has a fingerprint sensor and the M7 motion-sensing chip in the iPhone 5s, which works with fitness and other apps to sense how you move while you're holding your phone. And the company's data hubs HealthKit and HomeKit are designed to let iPhone users organize their fitness data and information from wired home appliances. There are also reports that Apple will introduce some form of mobile payment technology on the iPhone that will let users pay for products with just a tap of their phones.

The celebrity photo hacking incident has made many consumers feel wary about handing over data to a cloud. Apple has already said it will offer new options to users to better protect their iCloud accounts. And the company is counting on the idea that people want their phones to make their lives ever more convenient. 

What if I'm debating between an Android, Windows Phone and iOS phone? Apple's focus is to make a powerful phone with a low common denominator of technical knowledge, but there is no one-size-fits all phone out there. If you only use Google services -- or Microsoft services -- and have no interest in using iCloud, Facetime or iTunes, then a lot of the advantages of an Apple phone fade.

Apple's mobile operating system is more closed off than Android's by design -- a design decision that makes it stronger against malware, but less customizable. App developers still normally release iOS apps first. But there are whole genres of apps on the Android Google Play store that are unavailable to iPhone users because Apple's not so keen on letting outside developers monkey around with its software. For example, apps that let you change the dialing keypad on your phone, change the layout of your text messages or let you completely reorganize your home screen just don't fly on the iPhone. If you want to use apps like Aviate or Hello SMS on the iPhone, you're out of luck.

Apple is opening up on some fronts. In June, Apple said that it will let developers release apps to customize the iPhone's keyboard, so users can try different methods of input such as swiping -- just gliding your finger from key-to-key to type instead of the hunting and pecking we all use now. But if you want a lot of control over your phone, or even just the option to uninstall standard apps without having to jailbreak your device, then you may want to stay away from the iPhone.

Will I be able to afford the new phone? There are rumors that Apple will be raising the price on its phone due to its predicted larger screen and fancy new components. That may raise its price, which is already pretty high at $199 for a subsidized phone with a two-year plan and $649 for an unsubsidized model. New plans from carriers have reduced the cost of frequent upgrades by slashing the fee you used to have to pay to get a new phone before your current contract ran out. But doing so is still not what you'd call a budget-conscious move -- you're still paying the full price of the phone, just in installments.

And for all that is exciting about a shiny new phone, remember that you may not want to pay for a bunch of new features that you won't use. If you're even remotely on a budget, it's worth thinking not only about getting what you pay for--but also about not paying for things you don't want. There's also no shame in upgrading to last year's model when Apple slashes its price, something the company has done every time it's introduced a new phone.

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