Although I'm a fan of not over complicating things; generally when you re-build something for someone and they see the potential of their new site then 1 of 2 things happens.

1, They let the site go stagnant again like their previous site. 2, They want to build more on top of their site.

I always build a site like a client is going to come back to me for more work. I never work on the expectation to build and forget.

In most cases, the client ends up coming back to me for more pages. I've generally built this in a CMS so I charge 1 hours work for something that takes me 30 minutes to sort out for them. There is a client service there where I am doing them a service. I make 30 minutes profit per page (at a min charge of 1 hours work at a time) and everyone is happy.

The beauty of this method is that I am not coming back to a site in a year and wondering how I built it. Did I put navigation on every page? Were there differences on some pages?

I say Yes to not over complicating, I say No to not over complicating at the expense of making it complicated again for yourself to modify in the future.

EDIT: Typo