What do "Mindfulness" advocates say about planning for the future?

“It sounds like the whole time that you’re awake just focus on every little thing and nothing else? Is that correct or not?”

Not. Your assessment is a contradiction. “focus on every little thing and nothing else”. There is nothing else when you focus on every little thing. And no one can ever focus on every little thing at the same time. That’s called chaos. The opposite of mindfulness.

Mindfulness is simply that state in which one guides their own actions and thoughts by vehicle of reason, instead of emotion.

Mindfulness is a therapeutic technique used in contrast to the state of semi-consciousness many people get buried in as adults. It is not something that anyone I know of “advocates” as if it were something to do all the time and never be any other way.

“a mental state achieved by focusing one’s awareness on the present moment, while calmly acknowledging and accepting one’s feelings, thoughts, and bodily sensations, used as a therapeutic technique.”

I don’t know what sources you are looking at, nor what you mean about texting/talking while crossing/driving. Those might be examples of having your attention on something other than what’s going on around you in a practical situation – an example of non-mindfulness being dangerous. I suppose it is true that people who don’t practice mindfulness or meditation may be more prone to being lost in thought or mobile phone activities without noticing they’re in danger, but that seems like a distracting example.

I think you’re confusing instructions for how to practice mindfulness exercises when doing nothing else, as if it were telling you to do that all the time and never think in other ways. No one advocates that, except during an exercise. Someone might try it for extend periods if they were going to go on a meditation retreat, but it’s not a suggestion for what to do to an extreme degree in modern life all the time.

But they train people so that they can practice it in their daily lives, not when they are on vacation or on the least hectic times. I’m not sure how it’s supposed to work in practice? Say you’re in the kitchen cooking and your kids are there doing their homework, (they are being helped with understanding a questrion by you, ...., and a plumber is fixing something in the toilet, ....whatever else. How do you apply mindfulness?