Hi Holding - the issue of retainers and attorneys vary from attorney to attorney. In my type of work I generally do not charge retainers. But in the few cases where I do charge then I ask for enough up front to get me through a certain point in the case. I would think that a D attorney would charge enough to cover setting up the file, prepareing the petition, and filing it in court.
as to any refund - I belive that it is unethical for an attorney to keep any unearned fees and those fees sould be returned. In other words, if the A ask for a $3000 retainer to be offset against hourly billing of $200/hour and he only works for 5 hours on your case then he should return $2000. If the attorney does not then you might check with the State Bar on the ethical rules in that area.