During my first year or so as an independent advisor my average client relationship was around $1.3 million. Then, with the assistance of The Great Recession, specifically as new clients came aboard after taking a rather severe hit in their portfolios, my average is now closer to $500,000. One of the key questions an indie advisor must address is that of a minimum AUM level. Should you turn down clients who have less than $X? Considering that it takes about the same time and effort to manage a $100,000 portfolio as it does a $1 million nest egg, I'd say you must initiate some minimum.
My minimum was $250,000 before 2008. Now I set it around $150,000. That's not to say that I wouldn't accept an account of $125,000, but as a rule, I'd like to see at least $150,000. If the client has slightly less, but have a healthy income and are able to make ongoing contributions which would bring their account to the minimum AUM, then I would probably accept it.
I remember reading a survey a number of years ago which found that clients with less than $100,000 were much more likely to call you on a more frequent basis than those who had greater wealth. In short, the smaller accounts may take more of your time and pay you less, which is not exactly a recipe for success.