The amount of time that astronauts stay up in space is around 6 months before they are ready to return to earth and hopefully make it safely back to earth.
On a spaceship in space there are between three to six crew members on board the spaceship at all times.
So if you were to go to space in a spaceship you can expect to be up in space for at least 6 months although sometimes if something goes wrong they may need to stay an addition few days or a month more.
But most times a spaceship will be returning to earth within 6 months and hopefully the spaceship makes it safely to earth without any problems.
There have been some spaceship disasters years ago when astronauts died upon returning from space to earth.
Although a lot of spaceships successfully return to earth without any problems.