At a previous company, we had strong feedback from sales that prospects thought our legacy, cash-cow product looked old and outdated. They were right, and those first impressions are hard to shake. We lost deals (in part) because of design.<p>We did a minor design update in a beta release that introduced ~30% more vertical padding in lists. Beta testers (long-time customers) <i>hated</i> it. They were pros. They could not only handle the density, but the density enabled key workflows that the additional padding broke.<p>We ended up making the whitespace preference-controlled. Defaulted to on for new users; defaulted to off for existing users. Solved the sales problem while keeping our long-time customers happy.<p>For infrequently-used tools, especially transactional ones (e.g., Google Maps), additional whitespace seems to improve legibility, usability, and ultimately engagement. For power-user tools like GitHub in which users spend hours of their time every week, I want to see an industry shift "back" to denser UIs. Power users can handle them and typically benefit from them greatly.