An important thing to remember in search engine optimization is that using the word "and" in a page title means you should have two different pages as opposed to combining two phrases on one page.
What does this mean?
If you're an agent who supports many cities in a particular area/county, you (or your webmaster) may have combined city names (or counties) in your page title. For instance your page title may read:
"North Dallas and Collin County homes for sale"
This is not the right way to market your page.
The search engines when crawling your page will delete the "and" from your page title. So what you're really optimizing your page for is: North Dallas Collin County homes for sale. Not many people will search Google for this phrase.
Your best approach would be to drop the "and" and split the page into 2 different pages. One page being "North Dallas homes for sale" and the other being "Collin County homes for sale"
Always remember to use one page for one subject. Don't combine terms or subjects and you'll find yourself ranking higher in the search engines.