With technologies available today you no longer need a web designer to make little changes continually. In 1999 it was necessary, but today we have better solutions available.

Let's start with your site should allow you to change wording without anything more than a click. See Enhance Site - Easier Editing.

You should strongly consider adding informal regular written entires, or a blog, to your site.  This lets you easily add your thoughts anytime, sorted by date.  For example you may use the blog just for "news" items in it's simplest state, however it can be MUCH more powerful repository for information that search engines find and point visitors to your site. Enhance Site - Blog.

Keeping your content "fresh" (updated often) is a great way to enhance your search engine PageRank - This will help you have higher (more relevant) search results. One simple method is give your visitors the ability to "comment" on your pages, this both gives you feedback from them, AND keeps your content fresher without your effort: Enhance Site - User Comments.