Good question ! Time travel can be a fun topic, but also get incredibly messy very fast.

What happens if you go back in time, fall madly in love with your grandmother when she was young and you don't recognise her, and shoot your grandfather in a fit of jealousy ? To me, the nearest proof that there is either no time travel, or that it's purely a "spectator sport" is that Hitler wasn't assassinated some time in the 1920's, and that the crucifixion of Jesus isn't awash with time-tourists. But it's possible that time adjusts to whatever changes get made. Perhaps Hitler is a less bad outcome after the assassination of someone else who filled his role but without anti-Semitism, meaning that Germany was able to develop and use atomic weapons during WW2, leading to 150 million deaths and a totalitarian victory instead of "only" the 50 million killed in our timeline.

So there are lots of questions about the way time travel would work. The one thing that's without doubt is that it would never become available to the mainstream. With so many opportunities to settle grudges and generally mess things up, humanity would be extinct in no time !

Personally, I'd stick to being a discreet visitor and observer. I'd love to see the pyramids, Troy and Jericho being built, and a Roman Triumph parade. The ancient world (especially the Bronze Age, and the transition from hunter-gatherer to settled life) fascinates me.

The future makes me nervous; I have a bad feeling that going forward 100 years I'd either see an AI-controlled dystopia, or a blasted radioactive wasteland. But I can't rule out going a very short way into the future to pick up the winning lottery numbers, the exact date of the next Bitcoin or memecoin ATH, and the results of some key sporting events. I'd definitely do a small-scale test before going all-in, just to make sure there isn't an "observer effect" that messes up the get-rich-quick scheme !