Design for the user with the oldest phone

Design reviews often happen on fast laptops with large displays. That is the least representative environment your product will ever run in. The users who determine whether it succeeds are frequently on something much more modest.

Constraints improve design

Working within a small screen, a slow processor and a metered connection forces clarity. Fewer elements, stronger hierarchy, plainer language, no decorative weight. Every product we have designed under those constraints has ended up better for users on every device.

Practical rules we work to

• Assume the connection is metered. Every kilobyte has a cost the user is paying.
• Assume the screen is small and the fingers are real. Minimum forty-four pixel touch targets, generous spacing.
• Assume interruptions. Save state constantly so a phone call does not destroy five minutes of typing.
• Assume literacy varies. Plain language, short sentences, and never rely on colour alone to convey meaning.
• Assume assistive technology. Screen readers, large text settings and keyboard navigation are requirements, not enhancements.

Test with the people who will use it

We run sessions with actual users on their own devices, in their own environment, during their own working hours. It is uncomfortable, because assumptions fall apart quickly. It is also the cheapest way to find out you built the wrong thing before you built all of it.