Multiple database users vs single user?


Staff member
In a shared hosting environment where I have several websites under a single account. As an example suppose I have 5 wordpress (or joomla, drupal, etc) sites. Each website has a separate database and (so far) has a separate database user as well for each site. The sites are all under my control; there is no client for which I need to worry about keeping things separate. As I get ready to add an additional site, I'm starting to think it would be convenient to have a single shared database user that can access multiple db's rather than individual database users.

What are the pros/cons of having a separate database user for each database-backed site vs having a single database user that can access all the site's databases? Is there a best practice?