In the old days of the web it was common to see an 'under construction' icon on a page that hadn't been written yet.
Nowadays that is seen as bad practice; you should only ever link to existing content so that users aren't misled into thinking your website has content that it doesn't.
But my experience of website design tells me that it's only the smallest websites which are ever "finished" - ie all the content has been written and added - but larger websites are always going to change and be added to.
Just think how often prices will change, or staff will leave or arrive, or new products or services get added? Most websites (even the smallest ones!) will need to have at least some of their content updated at least once a year.
And then there's the design.
My own website is barely a month old, and I'm already on the 3rd version of the design:
There are still pages to add and tweaks to do. I wonder if a web designer's website is ever "perfect"?
Design for today
I guess the other thing I've learned is that you need to do the best design you can for now, but expect to revisit it every 2-3 years as the design starts to look tired or a bit old-fashioned (trends change even in web design!).
Standards-based web design
One of the great leaps forward in web design some years ago was the creation of standards-based design using HTML and CSS.
With a standards-based website, the HTML purely covers the content and structure of the website - the text, images, headings etc, and what follows what - and the CSS takes care of the layout and design - the colour scheme, and where things go on the page.
So with a small change to the CSS your website can change from purple to pink, for example, or you can add a background image or change the colour of Headings. And the change will apply to the whole site, just by changing the one CSS file, rather than you having to change the Heading colour on each and every page of your site (a chore unless the website is very small!).
So standards-based design makes for re-usable design - or should that be re-usable content? You can give your website's "look and feel" a makeover without having to change the content and structure of every page on the site. This means that updating your website every 2 or 3 years becomes less of a major upheaval.
Using standards helps Accessibility too
I've always been an advocate of making websites as Accessible as possible to people with varying abilities. browsers and hardware.
Using standards-based web design also means that your website will be more likely to be Accessible to (for example) a blind person using a "browser" which reads and describes the website to them, rather than them seeing it.
So standards-based design really is something that every website designer should be doing - I certainly do!