When I was younger I learned about time dilation and since my story was (and is) set post-planet I thought many hours about how to handle it. I came to the conclusion that I could just drop it and barely thought about it again. Now I can finally ask if this approach is justified.
As an author, of course I can just ignore physics and write what I want, but if that was my plan I wouldn't have given the problem so much time in the first place. So here are my thoughts:
- In my setting for some reason almost all intelligent lifeforms are human-like (they have the same ancestor lifeform).
- I recall that we humans react poorly to heavy gravitational changes.
- Hence all inhabitated planets should have gravitation about 9-10 m/s².
- Hence time dilation on inhabited planets is not practically noticable by the lifeforms.
- Therefore I don't have to deal with time dilation in my stories unless there is a very specific event.
Are there any mistakes in my reasoning? What are your thoughts?
EDIT: The usual planetary travel is almost immediate teleportation, which is backed up by a magic-science-combination, including worm holes. The second-to-most travel relies purely on wormholes. There is no other way (known to me), e.g. you can't win a race against light if you too are using the same road.
Time dilation is a thing that happens all around us, just too small to notice. There is a time dilation effect between the netherlands and the himalaya because of the gravitational difference, but we ignore it. I feared the effect could become more notable between planets with greater gravitational difference. Also our galaxy spins, but around what exactly? I think a black hole and being nearer to it or too far away may also have time dilation side effects, so I'm keeping the interesting stuff happening on planets which are not too near to the center or rim of the galaxy.
EDIT: I think all answers are useful to me and I really would like to thank you all. I marked the most useful one as accepted, but the favourite of the community is my runner up ;-)