Deletion of very old adds

Dear sir/madam,
I have to state that most of the very old adds are still displayed at the site in both "rent" & "sale" categories e.G. For more than six months. Policy may be revised to automatically delete those adds which complete the period of maximum of 03 months in terms of "sale" and only 01 month in terms of "rent". This will certainly enable us to find the fresh property for which we are always looking for.
Hope that you will review my proposal.
Thanking you.
Muhammad aamer