I gave some advice some time ago about dumping a site after a few months if it was not performing and not bothering with re-registering the domain name. Move on I said!
However I have change my mind. Most domain names cost just a few dollars a year and the age of a site does seem to matter.
I have been running a site about the http://www.greatwallofchina.cn/" Great Wall of China for a few years and nearly sold it off last year as I never bothered updating it, the traffic was low and it made little money.
The site now has a number one ranking on Google for http://www.google.com/search?hl=en&q=greatwallofchina& which quite a few people seem to type in!
I have done little to promote or get backlinks for this site yet it is still pulling in over 100 unique visitors a day, which is not too bad for a niche site thats rarely updated.
So is it the age of the site or the quality of the domain name / relevant country extension that is important here?
Either way it is hard to tell but there is two things to learn from this. The more websites you have the better and the age of the site seems to be significant in ranking so don’t neglect or let go of those early sites.