I just did another search on doctypes and found
DOCTYPE declarations are technically optional, and not using one does not cause an error; for example, you can create a Web page without a DOCTYPE declaration, and Microsoft® Internet Explorer, Netscape Navigator, Mozilla, and Opera may all render the page as you intended. However, as your Web pages become more complex, lack of a DOCTYPE declaration can cause pages to render differently than expected or desired. (This is sometimes referred to as "quirks mode.")
So if my webpage appears fine on most browsers, I should forget the doctype??