“Does using your website come back to me intuitively, after some time has passed since I last did so?”
When Michael Aldrich invented eCommerce, he didn’t assume it would work in 1984 for B2C, just because it worked in 1979 for B2B. He made sure it would work regardless of time and context, by UX testing in both instances.
His approach illustrates a point that’s super-relevant to today’s online retailers – a change in time is often accompanied by a change in context.
If a user hops on your site during a morning train ride, then goes back to it in the evening, they’ll probably be using different devices each time.
Of course you need to make sure that your design is so easy to grasp, that even on the same device, people can return to it without straining to recall how it works. But most eCommerce sites seem to have that down.
Multi-device experience, however, is still an issue.
Especially because responsive design ≠ multi-device optimised. Shrinking your website makes sure everything fits – it doesn’t make sure things make sense.