Before worrying too much about your storage space, it's worth knowing that users in small to medium companies on average don't even come close to using 1GB of storage.
Whenever you come close to the limit we will give you a heads up so we can follow up together. Just so you know, you can always save all your data without any errors. You don't have to worry about data that suddenly can't be saved, or us forcing you to move to a more expensive plan.
Besides this we are looking into the option of making the storage per user/account visible for our users, right now you can't view this yet.