I would agree with much of the above, and honestly, it depends on the current scene.
For example.
I tend to keep 17% free in cash in any account. That's lower than most professionals recommend, but then again, I've been at this a long time, so I'm well past my rookie years.
But the cash kept in my accounts grow at about 4.47% So any investment I make should do better than that, just to do better than what it could make sitting in my account. That's important to keep in mind.
But at the same time? Right now the U.S. Dollar is worth jack-diddlie. And I like to travel a lot. Sometimes within the U.S., but many times I go outside of it. And when I do, I tend to spend a lot of my money. Currency exchanges do mean a lot to me, and I look for the best exchange. I'll be going to the Czech Republic again soon. The exchange there used to be great. But with a weak dollar? And with the Czech Republic joining the E.U., and moving to accepting the Euro? Plus a weak U.S. Dollar thanks to that Fed rate cut? I'm going to be hit.
So the logical thing to do, is to invest more than I usually would of my cash sitting in my account.
For a rook, 25% cash is preferrable. But as you gain experience over the years, you will find that that number will shrink.