You cannot expand an iPad's storage capacity directly. The device's unibody construction does not allow user upgrades, and any attempt to alter the iPad's hardware may damage it and void any warranties. If storage is a primary concern for you, purchase the largest-capacity iPad available: 64GB as of the date of publication. Whether you have a 16GB or 32GB iPad and don't want to buy a larger one, or you have a 64GB iPad and are running low on room, you can use external or virtual tools to expand your options.
How it Works
The iPad uses flash memory chips (completely unrelated to Flash programming) instead of traditional hard drives. This allows the iPad its mobility but limits the size of the storage. Apple developers created the iPad as a companion device for your laptop or desktop computer. It allows users great mobility and long battery life, but these things come at the expense of storage and hardware versatility. Adding any hardware to your iPad reduces both its mobility and its battery life.
If photos and videos are taking up too much room on your iPad, Apple offers the iPad Camera Connection Kit. This kit has two converters: one that reads SD cards and one that offers a USB port. You can store your excess images on SD cards and view them on your iPad as you need them by plugging them into the appropriate port on the kit. Although the USB port on the kit does not support most external hard drives, the Sanho HyperDrive is advertised to work with the iPad to give you additional storage. This drive breaks your stored files into separate 32GB storage folders, so when you plug it into the Camera Connection Kit's USB port, the iPad identifies it as a camera and lets you access and store your files.
ITunes allows you to control exactly which music, videos, podcasts and other items transfer onto your iPad each time you sync. If you have too many TV shows and movies taking up space in your iPad's storage, you can free up space by clicking the tabs for each of these items when your iPad is connected to iTunes and selecting only specific items to sync. After connecting your device, and selecting it under "Devices" in iTunes left pane, use the "Summary" tab to select the option to sync only songs and videos that are checked. Using this method, you can load only the items you plan to watch or listen to during a particular week, and then re-sync the next week with different options selected, removing the videos you've viewed or songs you no longer listen to and adding a new selection. You can access these items again later through iTunes on your computer or re-sync them to your iPad.
Cloud storage service providers are great options if you handle large numbers of files on your iPad or need access to data-heavy presentations that you don't want filling up your storage space on a daily basis. Services like Dropbox, SugarSync, Box and iDisk all allow you to store files including documents, spreadsheets and presentations, as well as images, audio and video. Since the files are stored online, you can access them from your computer or iPad, but the mobile apps for these services don't require that you keep the data on your iPad after use. Sign up with one of these services on your computer and upload your files; from your iPad, download the service's app and set the cache size as small as you want it, such as 500MB. Any time you access a file from the service, it downloads to your iPad. Old files that fill up more room than you've allowed in the cache are deleted from your iPad but remain in online storage for later access. Most of these services are free for minimal storage and charge monthly or annual fees for larger storage capacities.