I think it's vital, but only once things have settled and you have a clear MVP. From that stage on tests and staging environments are crucial to scaling a product without all that hard work being killed by a poor UX
It's easy enough to use Keynote to show something, and I prefer that over in-browser mockups, but sketches and working prototypes are the best though. So long as the audience has an imagination, and you need to prime them them for that.
Some great lessons in this GDC talk on managing communities. Feedback is everything.
We use statsbot and value it, but giphy still seems to work when it comes to finding the right gif on a Friday afternoon :)
I feel that career changes are harder after a certain age, so the over 40s might be looking at the constant changes in work and struggling to fit in. But it's very clear now that you need to keep learning as you grow older.
I'm terrible at it, I find myself going around and around in circles. I've learned a little but I'm not great at negotiation, and I'm not sure it's something I can learn from a book.
I lose all focus and find myself easily overwhelmed by anything and everything. My mind races and I can't concentrate. The fix is endless list making until I exhaust that and tackle the root problem - the thing I'm putting off.