The amount of data you can back up with Dropbox Backup depends on the storage space available in your Dropbox account. The same applies to iDrive: Your storage limit depends on the specific plan you choose. If you reach your account's storage limit, you may need to upgrade to a higher-tier plan or manage your storage space. With Dropbox, you can easily make the most of your storage space by only backing up and syncing specific files. Although you always choose to back up whole folders or your entire computer when needed.