Google has announced that users’ 10GB of storage for Gmail and 5GB for Drive and Google+ has now been merged to 15gB of unified storage for free to use between Drive, Gmail, and Google+, which makes storage management a whole lot easier.
This means that you can use the 15GB however you want, for example you won’t be limited to 5GB in Drive even if you don’t use much storage in Gmail. You can use the whole 15GB for Drive if you wish.
Google is also making changes to the Google Drive storage page to allow users to better understand how the storage space is being used. Hovering over the chart will show a breaking of the storage across Gmail, Google+ and Drive. If you need more storage upgrades are available, which also means the change allows you to have more than 25GB in Gmail, any additional purchased space applies there now too.
Source: Google Drive Blog
