Hello,
It is important to always keep developing new relevant content. The value of a particular link can be affected by many factors and the age of a link can be one of them.
Personally, I believe many links are considered more relevant after they have aged for a while. I have noticed that links that are 3 to 6 months old and are of high-quality pass more ranking value that brand new links. Also, the quality of the traffic you are getting through those links is an important factor.
As links start ageing and producing more and more traffic I really think they get more value from the search engines.
Best Regards