Rachel Andrew posted a great piece for front-end developers about not trying to solve problems you don’t have yet. She specifically touches on over-the-top HTML5 boilerplates, adding polyfills for unsupported code, and trying to anticipate problems with older browsers before the site is even built yet.
There is some amazing work out there in terms of polyfills, frameworks and libraries. However you don’t have to use them, and in many cases won’t need to use them. So make sure every bit of code added to your project is there for a reason you can explain, not just because it is part of some standard toolkit or boilerplate.
A lot of front-end web development involves anticipating a whole host of problems with anything that’s built; it’s nice to see the opposite perspective just encouraging us to make sites and address the problems as they actually come up.