Last month there was a fair amount of buzz about how iPhone apps don't have much of a shelf life. According to a recent article at TechCrunch, the average free iPhone app is used for less than 30 days before it sits inactive on the desktop or is deleted by the user.

I guess I fit in with the average iPhone user to a certain extent. I have deleted apps that I thought were pretty cool in the beginning, but no longer catch my interest. But it might be different for me because I review apps, so I need to continue to make space on my iPhone every week. On the other hand, there are some apps on my iPhone that I go back to again and again, yet I can see how people would get sick of certain gimmicky apps. I would be interested to know whether your experience lines up with the TechCrunch article so let me know in the comments.

This week's apps include a handy cloud storage utility and a classic arcade type of top-down shooter.

Navigating through your files on ZumoDrive couldn't be easier. (Credit: CNET)

ZumoDrive (free) works in tandem with a downloadable desktop client (Mac or Windows) to let you easily move and use files between your desktop, your laptop, and your iPhone. Simply install the free iPhone client and install the software appropriate to your OS. From there, your ZumoDrive will show up like another hard drive where you can easily drag files that show up almost immediately on other devices. What makes ZumoDrive exceptionally cool is that it automatically understands not to store the big files on your iPhone, but gives you access to those files from the cloud. This means that you can have your entire 30GB music collection (or any other folder of files) accessible from your iPhone. It's important to note that the free version only allows you 1GB of space to work with, but you can sign up for several different monthly plans if you need more space. I think many users will be able to get by with the free version.

Sky Force Reloaded
Grab bonuses as you blow away planes and tanks to get the high score. (Credit: CNET)

Sky Force Reloaded is an excellent shoot-'em-up arcade game in the vein of top-down, 2D classics like 1943 and Xevious (Wikipedia links to games). Any child of the '80s and '90s who plays Sky Force Reloaded will remember hitting the fire button repeatedly at the arcade, as throngs of bad guys flew in every direction while bullets seemed to come from everywhere. Sky Force Reloaded captures the action from these classic games on your iPhone with satisfying touch-screen movement and eight levels of bad guys to blow away. You get three ships to choose from that balance armor and maneuverability to let you decide what kind of mix will work best for the onslaught. Like any good arcade game throwback, Sky Force Reloaded gives you an almost impossible boss at the end of each level to keep you coming back for more.

While there's no replacement for the joystick when it comes to control in these type of games, Sky Force Reloaded manages to make the touch-screen controls work quite well. You'll also be able to pick up better weapons, save countless humans, and gather medals for points. What more could you ask for in an arcade game?

What do you think? What's the shelf life for your iPhone apps? Do you have use for a cloud computing app like ZumoDrive? How far can you get on Sky Force at the hardest difficulty level? Let me know in the comments!

Jason Parker has been at CNET for more than 13 years. He is the Senior Editor in charge iOS software and has become an expert reviewer of the software that runs on each new Apple device. He now spends most of his time covering Apple iOS releases and third-party apps.