Old (expired?) Adverts

I am busy browsing the classifieds and have noticed adverts (cars and motorcycles) that have dates going back many months, even back to 2007. I must presume that some of these items are not longer available, or at least that the ads are no longer applicable. If so, perhaps it would be a good idea if the engine room at ThaiVisa Classifieds automatically removed ads after a certain period - or only allowed ads to appear for xx period (say 30 days?) and then dropped them. People could always re-advertise if they wanted to rather than having buyers getting excited about non-existent bargains. Not to mention a cluttered classifieds.