Edit what you want
Static Vs CMS
You can have a static website if you want. Its much cheaper to build. Its probably more suitable for a small business or individual who doesnt anticipate changes to content and who doesnt expect to build up an online presence.
Its more practical to have a website which uses a CMS (like Wordpress or Joomla) so that the client can take control of content on the website and make changes themselves. An entire website can all be created as editable content but this takes more time therefore it costs a little more.
Attract New Business
It doesnt matter if your website is brand new or has existed for decade there are always things that can be done to improve your rankings. Lots of business's have websites simply as a point of contact. Having your own website can be so much more rewarding to your busines. Think of your website as your own private sales executive. All you need to do it point him in the right direction and get him some contacts.
I specialize in SEO. This means that I can help your website get found on Google and other search engines with much more success.
Future-Proof & Flexible
With any new website or application its very important to decide how this will be built and which technologies will be used. A bad desicion at this point could be costly later on. If you want a website that has been built with much consideration for future development and improvements then its a long term investment that can grow and adapt as you choose. If its built without this consideration then its simply going to obsolete and sub standard very soon.
I always strive for a flexibility with clean code so that other designers and developers can work on it easily.