I learned about the space bar trick after 2 years of using iPhone after my son showed me a post on a forum. This made fixing typos much more quicker.

I discovered that about a year ago. I'm sure there are some other obvious things I don't know. In general, most of us who have been using smartphones for 10 years or so are probably able to adapt to new features fairly easily (assuming we learn about them). But it's probably easy to overlook how overwhelming they might be to someone who has never touched one before.