One by one, Google added services that all involved storage. It used to be 10 GB for Gmail, 5 GB for Google Drive and Google+ photos. Now it’s 15 GB total for free accounts and 30GB total for Google Apps accounts. Gmail, Drive or Google+ photos all count to the unified pool of storage. Not a surprise that this has happened, as it just seemed to be the right way to go. Some people use more for Gmail storage. Some use more storage for documents. Some upload a lot of pictures to Google+. With a unified pool of storage, you can use the storage as you see fit across the three services.
What if you need more? Google’s there for that too. For $4.99 a month, you get 100 GB storage. For $9.99 you can get 200 GB.
These changes will gradually be rolling out to accounts over the next couple weeks.
This is a good move for Google, and it makes it much easier to remember how much of your data you have in Google’s hands.