Humans will go extinct in a couple of jumps.

Either you also move all structures and equipment to the future or most people will die. Without a supply chain there is not nearly enough food to sustain all the people. Also, almost any object or building that could case a pollution problem when something goes wrong, WILL cause this problem when unsupervised for 75 years. I doubt this will be a net profit for nature.

75 years is about the duration between WWII and today. Many WWII structures have survived more-or-less intact, and many middle-age structures have survived for longer than that. Stone structures are pretty durable, especially if they are somewhat protected from the elements (or, better, underground)... although if you're underground, getting out might be an issue. Not dying in the first 24 hours is very do-able. It's after that that you have real issues.

One jump is devastating and will reverse people into the pre-steam era. another every 25 years? humanity is looking at the perpetual dark ages.

It could be fascinating to explore the politics of how each nation responds to the events. On a nationwide level do they ignore it? claim its a hoax? issue 'general advice' but don't do anything? or actively believe it and look to diminish the effects? On the level of individual businesses, one could also imagine a range of responses from 'you are fired if you do not work as normal', right through to 'we don't know if this is real, but as a precaution we are closing the business for a week in advance and giving our employees the time off at a full salary'.

A very weird premise. Conceptions of "saving the world" typically includes humanity, not in spite of humanity.

Your question provides a lot of details about how this works, and some of the existing answers rely on your protagonist knowing those details; but your telepathic message doesn't provide those details. Can you clarify your expectations on this point?

@fredsbend: You're right about what they typically do, but there are certainly exceptions, such as VHEMT, and science fiction has successfully considered such things, as in Asimov's "The Last Shuttle". Since the OP's premise doesn't include any information about who's doing this, there is a whole universe of possibilities.

Considerable deaths is a vast understatement you are looking at the single biggest loss of life in human history expect the vast majority of people to die in the initial transfer and the few months that follow, starvation, violence, and lack of medical care will go a long way to killing those that survive the transfer.

I see this as being a much darker version of Terry Pratchett's The Long Earth. I wouldn't mind reading a book with this premise

You really need to read The World Without Us en.m.wikipedia.org/wiki/The_World_Without_Us , a non-fiction book that is a thought experiment on what exactly would happen to the built and natural environment if all people suddenly disappeared. It covers many things of relevance to your situation.

Be where you're supposed to be when you're supposed to be there. Stand in the middle of corn field in Iowa. After that, it's standard survival tactics. One question per question. The first was about not dying in a sky scrapper; didn't even read the rest after realizing you were simultaneously violating and ignoring relativity.

@Jedediah: No, we’d just go back to a hunter&gatherer society.

"Might need to do overtime to get the day off" - why? Who will enforce it? There will be no workplace or organized government to held you accountable after the jump if you just silently walked away.

"Create a supply-stash (Drinking water, preserved food ...". I doubt there's much food that lasts 75 years. Canned food doesn't magically last forever. I even wouldn't trust 75 year old water bottles.

Fun premise. If you want to explore this in a story, it may be even more interesting to explore the next jumps after the first, and what this does to society. One immediate consequence would be that infrastructure would start to be (re-)developed for very different timelines - people would start designing things to last 75 years. And knowledge would presumably go up in value a lot, since it would be the only thing that you can be sure gets transported ...

... another interesting question would be if people become more or less concerned about climate impact. Maybe less, because a magical being has appeared which seemed to take action for the humans anyway. Maybe more, because what is in the real-world a somewhat abstract concept (in 100 years we will have ...) is now something that most people could expect to actually live, see, and suffer through.

Note that if your god-aliens doing the time jumping can put a person in the "same place," they have to move that person through space and not just time to where that spot on earth will be in 75 years. The earth isn't just moving around a stationary sun; the sun (and galaxy) are moving very quickly through the universe. You already have enough going on to worry about that I would handwave the fall-from-a-skyscraper scenario and say that they appear safely on the surface of the earth close to where they left. They are already moved millions of miles very precisely- why not a bit more?

"I can't imagine most people being able to just "take the day off"" why not? that's one day every 25 years, surely facing the choice between certain death and at worse loosing a job, most people wouldn't just wait for death