An interesting #UX lesson from a *very* old blog post by, I think it was Yahoo?

Never do total UI overhauls. Instead, take your "target UI", the thing that you're trying to work towards... and just change one thing. A single thing. A small one, that's easy to get used to.

Next week, do the same. The week after that, do the same. Introduce the changes very gradually and very slowly, so that the end user never feels lost, and never suddenly has to adapt to a new UI to get their work done. Ideally they shouldn't even notice the change.

There's a reason that so many especially older folks kept insisting on using Yahoo services, despite the severe mismanagement within the company.