Six tips on how to free up storage space on your iPad, iPhone, iPod are described at this site, sent to us by Jim Hamm. He includes this suggestion, "Another tip is to frequently close open apps, as they all consume memory as they run in the background. If, say, your iPad seems slower, I bet that available memory is about gone and this slows down the iPad. Many of us -- me included -- often forget to close apps after we open them, on an iPad or iPhone.
"Double tap the Home Button to view all the running apps along the bottom of the screen. Yes, they're all running and consuming memory. Close them and your device should run quicker."