Design for the imperfect day.
An interrupted task can become much larger than it looked in a design review. A comprehensible return gives some of that effort back.
Consider a person halfway through a form when their phone loses its connection. They wait, try to submit and receive an error. When the page reloads, their answers are gone. The form was short in the design review. It has become long in their day.
The difference is the repeated work. The interface asks for the same attention twice and gives the person no way to recover what they already supplied. Someone with spare time may repeat it. Someone between appointments may leave. The information requested did not change; the circumstances required to provide it did.
Design reviews give a product unusual advantages. The connection works, the screen is easy to see and the people examining it know its purpose. A customer may be using one hand, working in glare, or responding to an interruption. A control that appears forgiving at a desk can become a precise physical task on a moving phone.
Coming back to unfinished work
Review interruption as part of the task. Stop someone after they have supplied information, let them return later and see whether the product makes their place understandable. A usable return includes the work already retained, what remains to be supplied and whether anything has been submitted. Restoring an empty form and restoring a completed draft are different experiences.
Preservation needs boundaries too. People should know what is being retained and have a way to clear it, particularly on a shared device. Keeping every answer indefinitely would solve one burden by creating another. The product needs a deliberate decision about what progress to preserve and how to make that decision visible.
There are conditions a team will not imagine correctly. Pretending to be tired or distracted is no substitute for observing someone with different access needs. Familiarity with the product can conceal a barrier even when its makers are trying hard to notice one. The people affected need a chance to show where the design asks too much.
The form in the opening did not ask for more information after the connection failed. It asked for the same effort again. That difference stays with us when we think about a product being easy to use. Returning to saved answers and a clear next step can keep a small task small, even on a day with little attention left for it.