A true consultant has nothing to give you but their time. They sell it. You may get and need only one visit. Or he may meet briefly and include help in filling out the IRS form for settlement and compromise. You are entitled to know what you will accomplish before making the appointment.
Consultants have assistants.
Their main job is to filter out extraneous inquiries so the boss can do paying work. Talk to the assistant about how the consultant does business. Before you choose a consultant, get a referral. The best referral is someone who has actually used this consultant. An alternative is a trade association list that shows who belongs and is active.