system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU] If Dr. Strange could sling-ring from Titan in Endgame, how come he was so concerned if Tony could fly the space donut back to Earth in Infinity War?

Do we know what the limitations are of the sling ring? Has this been answered/addressed somewhere?
gpt
I think he only became aware of its true potential after going to Titan.  All we know for sure about the Sling Ring is that the user needs to clearly picture the destination, wherever in the Multiverse that happens to be.  Considering it can take the wielder to other realities wholesale, distance on the same plane shouldn't be a big issue.

But after seeing the "One" timeline, Doctor Strange knew the ring could do it because he already saw himself doing it.  Time's a funny thing.