If your web site is not looking good on a mobile devices, it will be less promoted on the SERP, because approximatively 30% of the search traffic is now mobile. Why push bad looking sites while Google can promote great experiences to demanding users ?
This nice change will be effective as from the 21st of April.
Spade is pushing for mobile first design, or responsive design for more than 4 years, most of our customers have nothing to fear from the upcoming change, their websites are future proof.
If you disregarded the mobile shift in the last years, you could test your site using the Google Mobile friendly test tool and you should consider adapt your site quickly to keep a big chunk of your “natural traffic”, but also to please your audience, not only others websites have mobile users.
Contact us if needed, we might help.