Time travel doesn't work unless you also have teleportation. If you travel to the past/future, Earth will be in a different position in its orbit, and you'll die in space.

That’s why I always liked approaches that use a physical machine that has to stay in one place for an extended period of time. Quantum Break’s hard sci-fi approach to this was fascinating and kept making me reconsider how the time loop worked. Highly recommended for time loop nerds like me.