Also, any changes that you wish to have Moose Enterprises make to your site will also cost extra unless you have maintenance. Changes to your site will be billed on a time and material basis unless you have elected to purchase maintenance. Maintenance is an agreement between you and Moose Enterprises to provide support and make changes to your existing site. In return, you are allowed up to 20 changes to your site per year. A change is a modification to a page on your site.
Maintenance is optional.
However, if you choose not to have maintenance for several years, and then wish to go on maintenance, you will be charged for the years you were not on maintenance. Lets say you wish to have a 5 page website developed. Now, suppose you want to do it on a shoestring. Oh, and no maintanence - you'll pay as you go. URL stands for Universal Resource Locator.