As a web developer, i regularly have to test my work in all browsers to see things look and behave the way they are suppose to. It is a must to check your website in all browsers to see how it looks, weather the design is not broken.
Most often you will test your site with one browser and make it working for that browser but your users/visitors will visit your site for all kinds of browsers and platforms. Sometimes you will find that your site/template looks fine in IE7 but breaks in IE6 or vise versa.
Its mostly in IE where you will experience hick up with your website. I use this tool to test my work in multiple IE browser so see it looks okay.
http://tredosoft.com/Multiple_IE
You can use this tool for free. It will install IE 5.0, IE 5.5, IE 6.0 and IE 7.0 to your computer and you can test your website under all these browsers.
Note that IE 5.0 and IE5.5 are discontinued and nobody seems to use them. However, IE6 and IE7 are widely used next to firefox. You have to make sure your website compiles fine under these web browsers.
test your website design in multiple IE browsers
Linear Mode
