Does validating HTML matter
A web page does not break if a page does not have valid HTML. A web page may not even look different if a page does not validate. Browsers are made to display broken pages and they are made to allow less experienced web developers to create websites like everyone else. So if a page works, if it displays correctly and if browsers are made to display all types of broken pages, does it really matter if our pages validate or not?
If we are using HTML that we don't create ourselves, such as open source components, then it doesn't really matter as we just don't have the time to fix up code that isn't really broken in the first place. We did not create the code and if we went around trying to fix other people's code that we think can be made better we'll never get anything done.
If we are writing our own HTML then it certainly matters. It matters a great deal. We are web developers and we should take pride in our work. We should try to be diligent at all times and produce our best quality of work each and every time.
If your a web developer and take pride in your work, make sure your pages validate. Not for anyone else, but for you and a sense of accomplishment.