The current workflow for checking credit usage information and reports is:
Organization > Status > Credits
Credit usage can be filtered by date into months, weeks, days and can be broken down by Feature Storage Usage.
Although, when looking at Feature Storage Usage based on individual feature layers by clicking on 'view item details', the Database Storage Details pop-up only displays current file size of feature layers. This inhibits users to determine feature layer credit usage for individual feature layers over a retroactive period of time.
Being able to generate reports that show credit usage by an individual feature layer over a period of time could be helpful to organizations who are hosting data for other parties on their AGOL.