We often get inquiries from clients about building them a new website. Many of them have websites already - websites that they hate for one reason or another. The content management system is too hard to use. The design is outdated. The site doesn't work on mobile.
Regardless of the reason, the client's answer to this is always "Let's just start from scratch." The client hasn't spent any money on a site for several years (other than hosting fees) and is ready to spend another big chunk of change and then forget about the site completely.
And most of these clients are right - they do need a new site. But that's not the end of the story.
The best sites, and the ones who's owners do not hate them, are those that are developed using iterative design. What that means is that building the site is never really done. We get a solid foundation built, and then keep adding and upgrading year after year (or month after month - technology changes quickly!) to ensure a high-quality, functioning site. Just like you might do with your home or office. This evolutionary system for website design, development, and maintenance ends up being cheaper in the long run for the client because they aren't throwing out huge sums of money every few years for a complete site redesign.
It's human nature to want to check a task off the list. We want to build the website and then not think about it again. We'd like to argue that instead of one big project, your website should be a series of smaller projects over the life of the site. You wouldn't build a new house every three years, so why build a completely new website? Instead, add a room (page) here or an appliance (feature) there and your house (website) can grow with your business.
You also might enjoy:
Don't Let Google Downgrade Your Website