Please note that your ad will stay on the site until you delete it, or until it expires.
The length that a listing stays on the website before it expires may vary from city to city.
Currently, however, below is a list of the minimum amount of time an ad stays on the site per section:

Classifieds: 30 days
Motors > Used Cars : 30 days for the classic package. (number of days change depending on the package you choose) 
Property for Sale: 60 days
Property for Rent: 30 days
Jobs: 30 days
Community: 30 days