If you’re asking about a maximum age, there isn’t one.  As long as the writer knows what he/she is doing, the age doesn’t matter.  I know 25 year olds who write like they stopped listening after fifth grade English.  And on the opposite end of that, I’m 37 (will be 38 in March), and I currently pull an average of more than a million views per weekly article.  So my age doesn’t really reflect the public interest in my articles.

Though, given, I write from that perspective — an older guy who’s sort of giving advice to a younger crowd.  But even when you take that out of the loop, the overwhelming bulk of my work has nothing to do with advice at all, and the average reader would be hard pressed to tag me with an age based on that body of work.

But if I ever lost touch with the actual audience, you’d be able to tell by the sheer drop in traffic, and at that point, I’d probably hang it up voluntarily out of respect for the website that made me.