Another even easier and quicker way to greatly improve UX in many products is better copywriting (possibly by hiring an actual copywriter).

Quite frankly, I know I'd be quite puzzled if a message popped up out of nowhere telling me "You might be logged out, please, back up your content and refresh the page!".

What do you mean by I /might/ be logged out? Am I logged out or not? And why would I be logged out? What does this have to do with anything anyway?

And what on earth am I supposed to do to "back up my content"? What does this even mean?

And what is this "refreshing the page" business all about?

To be honest, being a developer myself, I would actually figure out what you actually mean. But I can guarantee you that 99.9% of the people out there won't have the faintest clue of what you're talking about. They'll just do what they always do in this case: they'll click OK, or Cancel, or whatever they think is going to make the annoying message go away.