A web site is like a building. Over time it gets lived in. And, regardless of the initial intentions of the designer for how everything within it should be arranged, things get moved around, stuff gets added, some things get taken away, more stuff gets added, the occasional renovation takes place, and yet more stuff gets added. Many web sites are not really designed to be 'lived in' — i.e. to support all these changes by different owners with various intentions. After a while they bear little resemblance to any sort of coherent design and are likely to become increasingly hard to manage. Of course, it's impossible to plan for all the 'home improvements' that will happen to a web site between major redesigns. However, it is possible to be prepared so that the addition of something new to a page doesn't break its design. A good way to future-proof a web site is to create styles in advance for the most common page elements, even if they are not yet being used. This is called 'planning ahead' ;-) and is an activity often overlooked by web designers. Using the 'planning ahead' method, if a content author wants to add something to a page — say, ...