What's the point of valid CSS/HTML?

Question

If I\'ve tested my pages in most major browsers, why would I need to maintain a validated code? I want to use box-shadows and corner radius if they\'re supported in WebKit b

Answer 1

As long as it works in the browsers you care about then it doesn't matter. In theory your maintenance costs might be lower with validated code.

You have to determine what the success criteria for your project is. If your program does what your client needs then just because you code is "valid" doesn't make it more magical in and of itself.