How long it takes you to get somewhere on Earth depends on how fast you are moving, the distance, and what obstacles you have to overcome. For instance, if you want to go to the supermarket which is 10 km away from your house and you walk at an average speed of 5 km/hr it will take you 2 hours to get there.
Spacecrafts move much faster than people but it still takes time to get from point A to point B. It also depends on the route taken. Some spacecraft use a concept called gravitational assist to boost their speed and save on fuel and weight at launch. This can add years to the journey because the craft must arc around different planets in its orbit. The Pioneer 11, Voyager 1, and Voyager 2 used this strategy. The Cassini spacecraft took a more straightforward path to Saturn and that helped it reach the gas giant sooner.
The answer to how many years it would take to get to saturn is complicated. When you take into account the fact that Saturn’s orbit is elliptical and it can be as far as 1.21 billion kilometers from Earth at its closest and as close as 1.7 billion kilometers at its most distant, the journey can be quite lengthy.
For humans, it is even more challenging. The harsh conditions and high levels of radiation in the ringed giant’s atmosphere make it tough for astronauts to survive and operate the spacecraft. So, it could take a very long time for a human mission to get to Saturn – even longer than the time it took the Voyager spacecrafts to reach Saturn.