Studies show that today 90% of shoppers look on-line before making a purchase, and of those, 82% contact a business after a search. Having a website equates to having a storefront on the "Super Highway". If your competition has a website and you do not, prospective customers will find your competitors and not you.
Even if you do not sell directly over the Internet, having a web site gives you a way to communicate and share information with current customers and perspective customers.
If you feel your customers are older or are not on the Internet, think again. The fastest growing segment on the Internet are individuals from 50 to 70 years old.