We should all know by now that a website, regardless of the size, should be responsive. All websites whether they are small information sites or larger ecommerce websites, need to be responsive in order for them to work correctly on multiple screen sizes.
When programmers make an existing site responsive or build a new one from scratch, there are certain mistakes that are often quite common that need to be avoided. With new tablets and phones hitting the market every month, it would be virtually impossible to tailor your design around each and every one of them, instead you need to focus on screen size. Not all phones for example have the same screen size so making sites just suitable for phones in general will not always work well for your audience.
Although mobile device viewing has now overtaking desktop users, there is still a massive 42% of searches carried out on desktops and therefore it would be silly to only design your site to work and look good on mobile / small screen devices. Take full advantage of the added space you get on desktops rather than just enlarging everything to fill the page.