In Mack's excellant recent thread From Concept to Upload [webmasterworld.com] he says....
Because failing to allow for future website expansion during the very earliest planning stages can lead to very difficult choices in the future, I'd like to expand on that a bit. Mostly I'm focusing here on site navigation paths now and in the future as a site grows.
Predicting the Predictable
It's probable that anyone building a new website, business or hobby for that matter, has a subject for the site in mind, and that they have at least some kind of goal in mind, perhaps increased sales.
Simply focusing on increasing sales for your current widget line could be too narrow a vision.
It's always possible that success in one area will lead to customer requests for other areas or products.
Not planning, at least minimumly, for that possibilty can be pretty expensive in the long run.
If you have to redesign and rebuild your whole site to accomodate growth you'll see that pretty quickly. Redisgn and rebuilding can quickly eat up any savings from not initially planning for growth in the future. Worse yet, it can confuse the heck out of your readers or customers, never a good idea.
Predicting Possible Growth Areas Can Be Difficult
Even if you think you have all the possibilties covered, your users/customers might not agree. Allowance needs to be made so you can accomodate unforseen growth opportunities. Hopefully your emails from customers or readers will let you know about possible expasion opportunities.
For instance: You might offer a section on buying widgets, because you sell widgets. It might turn out that your happy customers would be even happier if they could come back to your website and learn all they need to know about maintaining widgets, or repairing, or collecting antique versions, etc.
Plan for Sideways Growth
It is not enough to plan for simple verticle growth,
Blue Widgets ¦ Yellow Widgets ¦ Green Widgets
¦-Big Blue Widgets
¦-Medium Blue Widgets
¦-Small Blue Widgets
You also want to consider sideways growth
Big Blue Widgets
¦-Big Yellow Widgets
¦-Big Green Widgets
Big Blue Widgets
¦-Repairing Big Blue Widgets
¦-¦-Big Blue Widget Parts
Build-In an Out
It may not be possible to predict every eventuality, so you need to think about this carefully.
Try to leave yourself one or more options for totally unforseen navigation paths through your site.