With mobile traffic overwhelming desktop for most websites and apps today, adopting a strategic mobile-first approach to design is utterly essential. Mobile devices present unique design challenges and considerations that simply can't be an afterthought.

For starters, smartphone screens are exponentially smaller than desktop displays. This drastically reduces the visual real estate for laying out content and functional elements. Mobile designs must prioritize the absolute core content and actions while making judicious use of tactics like hidden menus, scrolling cards, and progressive disclosure. Visual hierarchy and path clarity become even more crucial on cramped mobile screens.

Then there's the proliferation of mobile usage contexts to plan around. Most mobile interactions are dished out in bite-sized moments - standing in line, commuting, or splitting attention with other activities. Designs need to accommodate perceived performance limitations, periodic poor connectivity, and seamless transitioning between interfaces.