There's a famous Heinlein quote, I think it goes:

The confusing thing about the list is that, my impulse is to say it's suggestive, and he means in general you ought to know a lot, but he includes a lot of sort of basic things (or things that line up with his philosophy) that make me think, it's not an example list, it's literally, if you want to know how to juggle, it goes after these things. 

So, I know he lands the quote on "specialization is for insects". That sounds pretty cool! I'm not an insect. I'll learn whatever the ship thing is, sounds pretty important.

But specialization can (when faced with a lifetime of learning otherwise) be the primary way we individuate. Do we want a million Robert Heinleins? Perhaps! But not a billion. That's far too many people with precisely the same skills and interests and worldview.

That being said, I'm not saying "specialization is the measure of progress in civilization" (although it is). I'm not in team Not-Heinlein. Here's my synthesis of these ideas: learn more than one thing, and how to cooperate!

Plus, why not, learn the 'cooking a tasty meal' one, that one is good. A single tasty meal takes like no time at all to learn.

But mostly I just want people to realize the value of cross-domain expertise, and be prepared to cooperate in the giant distributed hivemind that is the global economy and communications systems. Have a (cross-domain) specialty, but don't have it be all you are. Have some other outlet. Know more than one thing.

Be a normal human. Don't make life a checklist of skills. Heinlein, for all his quotation, didn't appear to die gallantly. You've got to imagine some percentage of his recommended tasks were almost pure indulgences of his fantasies, and boy howdy did he have a militaristic fantasy. Make up your own mind, but remember he was a total weirdo living off the excess returns of being a sci-fi legend, and his life wasn't as constrained as your own situation might be.

In general, don't take advice ā€“ this is why I usually stick to 'follow your heart'. All the rest is fluff, or soon to be ignored.