A retainer is an agreed sum of money paid to the attorney to accept the case and begin representation of the client.  It should be made clear to the client what the retainer is paying for.  Attorneys usually work on an hourly rate and the number of hours spent on a case are deducted from the retainer as earned.  If the retainer is, for example, $2,000, assuming the attorney’s rate is $200 an hour, when he or she works on the case for six hours, the attorney will earn $1,200 from the client’s account.  If the time to complete the case is going to exceed the retainer, then the client is asked to replenish his account to allow the work on the case to continue.  The total fee in the case will be based on the number of hours needed to complete the case.  The attorney should be able to give the client an accurate estimate of the time and money that will be involved and explain what the estimate is based on.