If you're planning to sell or give away your iPad, then it is essential that your personal information and data be erased from it. If it's running sluggish after a few years, sometimes backing up your data, erasing it from the tablet and restoring it might improve performance.
Watch a video how-to guide on YouTube.
First, you need to make sure that you have the most current version of iTunes.
Once you're up to date, plug your iPad into your computer. On the iPad screen click "back up now." This may take some time depending on how much data and applications you have on your tablet.
After the iPad finishes backing up, unplug it and go to the settings menu (gear icon). Click on "general" and scroll down to "reset." Click it and then select "erase all content and settings." Your iPad will prompt you twice if you want to continue. If you've made sure that you've backed up your data, then initiate the erase. This may take some time depending on how much you have stored on your device.
After the iPad is wiped, it will prompt you for some basic information like which Wi-Fi network you'd like to connect to. When you complete this, it will ask you if you want to set up your iPad as new or restore information from a previous backup. In my case, I plan on keeping my iPad so I chose "restore from iTunes back up."
Plug your iPad back into your computer.
In iTunes a "Welcome to your new iPad" screen should appear. In my case I selected "restore from this back up." After a few minutes all of your data will be back on your device.