It is a question I am often asked by lawyers. Most asking the question are thinking about how they might squeeze anything non-client or non-family related into their busy schedules.
Here is my answer. "How much time are you willing to devote to taking complete control of your work and your life?" Every successful rainmaker I have ever talked to completely gets this question.
I believe that at a minimum a lawyer should never eat lunch alone (like the title of the currently popular business book). That translates to approximately 7-8 hours a week. This minimum is a great starting point -- whether the time is spent entirely on lunches or spread into phone conversations, other meals, receptions, etc. Depending on how many hours you work in a week this will translate to 10% to 20% of your time at your firm.
Are you committed to taking control of your work and life?