Here are some questions to take with when talking to prospective caterers:
Do you have my date available?
Have you done any events at my location?
What food choices can you recommend for my budget and guest list?
Can you accomodate dietary restrictions?
What is the price difference between a buffet and a sit-down meal?
Do you have a different menu and price for children?
How much do you charge for vendor meals? Do they get served the same thing as our guests or is it a separate menu?
Do you do food tastings? Is there an extra charge for this?
What types of linens, glassware, plates, silverware, etc do you provide?
What is your policy on clean-up?
Do you provide alcohol?
What is the ratio of servers to guests?
How will the servers be dressed?
What is your cancellation policy?
Please add anything else you think is important.