At the moment there is no user interface to check the used space so please request it at support.atlassian.com
There is also no automatic way of deleting old pages but is probably that you don't need to. Attachments usually count for the most space used and can be managed from the space configurations section.
Have a nice weekend! :)
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG