Website Maintenance is a big part of keeping your customers coming back. It also helps keep your website secured. Some people feel that it is not needed but it is very much needed. Besides the big security problem you could be facing, you run the risk of a person looking at it and realizing the info is even 2 or more years old, (don't forget about that copyright date either).
How would the person know it is relevant information to this time? How about if you are actually still even in business any more? Without an updated copyright date how are we to know the information is current. However, the worst is no copyright date at all. There is nothing that has a reference point of its date that you can tell when the information was presented.