You should, because while you may not, your web visitors do, and that is who is using your site, not you. Like mentioned many times in the support forums and other places in the Web, you should test your site via Netscape 3.0 and above, IE 3.02 and above, and even Opera 4.0 and above, to make sure that your web pages are interoperatable between different browsers.
Regards,
Eliot Lee