Typically, candidates are given a few days to a week to complete the take-home assignment. Usually recruiters warn candidates not to spend more than “a few hours on it,” but in reality many candidates spend a fairly significant amount of time. After all, if you really want to differentiate yourself, you have to put in the work.
So you’ve got a design exercise on your hands and the clock is ticking. To make sure your solution is adequate, you’ll need to make sure you understand the evaluation criteria. Every company will vary, but typically they look for:
Process. How you approach and solve ambiguous problems.
Craft. Strong interaction design and visual design work delivered in a short amount of time.
Creativity. Generating divergent and out-of-the-ordinary ideas quickly.
Prioritization. Converging on critical concepts that lead to impact.
Sometimes companies also use different types of design exercise formats when they want to zero in on a particular skill. For example, some may focus heavily on visual design aspects, while others may want you to focus more on interaction design. Typically this will be specified in the design exercise prompt.
And yet some companies may not have a rigorous process established (usually in startups) and they may not really know what they’re looking for in an answer. These can be the toughest take-homes to crack, but usually, following the design process to a tee and showing how your process has yielded new and interesting solutions helps put them at ease.