Internet Explorer 7 has been out for almost a year and Windows Update is now pushing it to most XP machines. Do you need to change your site? Probably not, but it is worth an afternoon of testing.

Most of the problems we have seen fall into three groups: layouts that relied on IE6 bugs to line up, PNG images with transparency that were hacked around for IE6, and old "best viewed in" scripts that sniff the browser version and send IE7 users to an error page.

Our advice: open your site in IE7, Firefox and Safari side by side, check the forms and the checkout if you have one, and fix what is broken. A full redesign is only worth it if the site needed one anyway.