where all the tablet makers seem to have stalled: battery life. Faster processors gobble up more battery power, so maintaining 10 hours of battery life from an old tablet to a new tablet probably requires battery improvements. Both new iPads have the same M7 motion co-processor that handles sensors, such as the accelerometer and gyroscope, saving battery power by not using the main processor. Other than an hour here or there, mobile devices makers seem stuck at the half-day mark, a frustrating limitation for people who have adapted by carting around chargers and scrambling to re-up anytime they spot an empty outlet at a cafe, airport or friend's house. For now, Apple is comfortable enough with the competition to just iterate on its well-designed, popular products, making the usual round of improvements and throwing in the occasional flashy feature to grab attention, such as fingerprints on the iPhone 5S. It may not be as much fun for tech fans who were used to splashy new products and well-kept secrets, but it's probably a solid business decision. According to Forrester analyst Sarah Rotman Epps, replacement tablet sales are growing faster than new new tablet sales worldwide. Manufacturers need to compete to keep the customers they already have who are considering upgrading from an old model. All the tablet makers are competing with what are essentially the same minor