Our existing method of moving between planets (heck, even the Earth & Moon) will take 9 months to get from Earth to Mars (or back). And the launch window is every 22 months. The return to Earth is either 4 weeks after you get to Mars, or 23 months later (so any fault that prevents a prompt return means you better have almost 3 years of food/water/air onboard).

Without some magical SF technology being invented, no, we're not going to see humans travelling to Mars in our lifetimes.

If folks are serious about human trips to Mars, there would be an effort to send supply ships ahead of time and stockpiling fuel/food/water/air in orbit around Mars. This would solve 2½ problems:

1 - Carrying supplies for both directions would require building spaceships bigger than we can currently build.

2 - If there is any failure on the way or at Mars, there will be stuff to let the astronauts survive until they can fix things or any sort of rescue mission could be sent.

And "that half" - Currently, the US has had a 70% success rate sending stuff to Mars (the Soviets had 50% success). Some of those supply ships won't reach Mars orbit. Some will break on the way there and drift past Mars. Some will smash into the surface of Mars.

Why send stuff? Supplying the astronauts on ISS requires sending 1000 pounds of stuff per person per month. And that's only 300 miles from Earth. And the ISS has water recycling, yet they still need water sent up.

My estimates for a successful "manned" trip to Mars (and return them safely to Earth again) would start around $200 billion.

https://en.wikipedia.org/wiki/Hohmann_transfer_orbit

https://en.wikipedia.org/wiki/Launch_window

This page claims Earth/Mars launch windows are every 26 months:

https://en.wikipedia.org/wiki/Exploration_of_Mars#Launch_win...