The part of a tablet that most often requires repair is the screen, followed by the battery. Apple's iPad support section has separate sections for these two repair types, while any other repairs fall under general support questions. Screen and battery repairs feature prominently on all iFixit tablet pages.
Repair shop websites from across the United States also show that screens and batteries are the most common repairs. As San Diego PC Repair notes, what users think of as the screen consists of the touch screen plus the LCD, two separate parts.
Screen problems can involve either physical damage to the screen or a screen that does not respond. Battery problems may be physical or software issues as well. If the problem is software, removing unused apps to free storage or resetting the operating system to factory specifications can clear up problems without a costly repair. Even physical replacement of a screen or battery is often cheaper than purchasing a new device.