Add a several features to Plans functionality
1) 'Send email in [...] day(s) before expiration:'
2) 'Set status as :'
3) 'Mark listing after submit as:'
4) 'Action when listing is expired:'
All these features you can see in the eSyndiCat Directory script: http://demo.esyndicat.com/admin/controller.php?file=plans&do=edit&id=1