A 16 GB iPhone makes sense economically, but if you take a lot of photos and videos , or download a lot of apps, your available memory will disappear in a snap.Though, if you just need a little more room on your phone for that latest download, there's a sneaky trick that can help.First shared on Reddit , you can gain up to 4 GB of phone storage by trying to download a too-large movie on iTunes. Here's how it works : Head to Settings, General, and tap About, then make note of how much Available storage you have. If you've got more than 8 GB there, you're likely fine (for now), but if you've got 5 GB or less, you should definitely try this trick.Next, open the iTunes store app, navigate to the movies section, and find a really big movie — one that is larger than how much available space you have on your phone — such as Lawrence of Arabia (8.19 GB) or The Lord of the Rings: The Two Towers (6.83 GB). Don't worry, you won't actually be paying for it or watching it. Tap the Rent button two times. You'll get a notification that you can't download it, with an option to hit "OK" or "Settings." Tap Settings.Now, get ready for the magic. Head back to General, About, and look at the amount of available storage you have now. It should be higher than it was before. According to Reddit, you can keep trying this process over and over, and it may continue to free up more space on your phone each time.We're not quite sure why this trick works, but it would appear that each time you attempt to download this iTunes movie that’s too large for your phone, it tries to eliminate some data it has cached (such as your Safari-surfing habits ) or other extraneous backups.If you experience some success using this method, we'd love to hear about it in the comments.