OK, first and foremost: No, you are not required to use grids or frameworks whatsoever. And my honest opinion is that all this bootstrap/boilerplate/grid system crap is mostly redundant, unnecessary bloat to the average web designer/developer. Unless you’re pulling off new major websites on a daily basis this is way too much overhead. Also I think before using systems that someone else has developed one should learn the basics of (semantic) coding from scratch. The problem of many amateur web designers/developers is that they are relying on frameworks and CSS preprocessors (which basically require learning a new coding language) without understanding what they are doing.
That said, I do also think that a grid as a design pattern
doesn’t limit creativity but actually allows for clean and well structured designs. Note that I’m talking about design
here, not code, and there is a great article about grid-based design on Smashing Magazine
. But it’s your choice whether your design is based on a grid or free-form. You certainly don’t need it for a responsive website.
Actually, about the only thing you need to make your website responsive is CSS media queries
. Don’t let yourself get distracted by all these empty buzzwords. Basic HTML and CSS is all you need, and if you learn it properly you will eventually either create your own reusable templates over time or you will learn when and how to use frameworks appropriately according to your actual needs.