I recently posed this question to Artist House on twitter:When or should an artist seek management?

In short the answer was when you can’t do all of the work yourself.

Another thing to consider is what a manager can really offer you. It’s great to find someone that wants to help your career, but they need to have three assets in order to actually help your band in such a capacity as PASSION,CONNECTIONS and CAPITAL.
On the Artist House Music site there is a blog that answers my question further and explains the reasoning behind either choice with videos.

Videos are of George Howard,Robert Reynalds:an attorney representing such acts as The Killers and Louis XIV, Nissan Wasfie:faculty member of Columbia College Chicago,Adam Levy: guitarist and songwriter of Norah Jones’ band,Blake Bundey of Milestone Music Management

please click here for the VIDEO responses to the question