What are the pitfalls of using box-sizing: border-box? [closed]

Question

I was recently looking at the box-sizing property again. I feel like border-box is actually a more appropriate model. I want my boxes to include the padding and border without needing to account for it every time in the width calculation, which is not really possible when using 100% width.

So the question is what are the pitfalls? Why should I not use border-box?

Answer 1

The only pifall I can think of it's that is not supported by IE7&8, on IE9 works fine