With iOS 7 you no longer need to download videos purchases on iTunes before playing them. You can simply press play as long as you have WiFi access. Just head to the Videos app and you’ll see all of your previous purchases. If you know you’ll want to watch a movie or TV show off of WiFi later, you can download it to your phone to store it locally using the cloud download button.
If your purchases don’t appear there, go to the Settings app > Videos and make sure that Show All Videos is turned on. If they aren’t there, they were likely purchased using a different account.
Later, you can delete individual videos to free up space. For movies, go to the screen where you see the thumbnails of your movies then tap the Edit button in the top right corner. Tap the X in the upper left corner of the thumbnail. This will delete the video from your device, but you’ll notice that the thumbnail is still there, but a cloud icon on it. To delete a TV episode swipe from right to left across the episode and choose Delete.
Streaming videos can also be sent to a friend’s AppleTV via AirPlay. It’s the modern equivalent of bringing your DVDs or videotapes to a friend’s house for movie night.