We've reached the 75th topic nuckers! Time to debate!
The two questions that were asked were "How does time travel work?" and "Who should be able to use time travel and should we limit it to certain people?" in case you forgot. Welp, begin!
Honestly. it should only be used when its an option. Like for example Junior had no other option but to go in the past and stop Blacklust from upsetting the timeline. It should depend on the seriousness of a problem.
On the off chance its for fun, there shouldnt be a limit, unless there is a major reason invovled in a situation.
And how should it work. Chaos Powered Technology.
I feel like using an idea as though there should be a strange walnut shaped object(as a time travel device, it'd be easy to carry around with you due to the size, too.), which when crushed gives you a number of times to leap through time? And the higher you leap the further back in time you go or the further you leap just an idea which also limits Time Travel to a fair point.
Time travel should work in that a device takes in energy from a 'warp stone' embedded into it, the the possessor of the device can think of a date and time and they would warp there instantaneously. However paradoxes can be created and since it's highly dangerous, only those who possess one of those device specifically made to time travel should be authorized to do so. However, other methods of time travel can happen as well, though without one of those devices it could risk malfunctioning. However the knowledge of these devices should be top secret known only to the possessors and the creators. Side-along time travel is possible, via holding onto someone with a device. There should be around 100 devices only, though the other methods are not regulated.
Those who can use time travel is anyone, provided they possess the means to do so, and I think that time travel as a power should not be allowed, just with machinery.
EDIT: I FORGOT ABOUT THE TIME STONES
Edit: Like what Blu said, multiple versions of the same person could be present via time travel, seeing your past or future self would be fine and not cause anything, though a paradox would be something along the lines of what Blu says as well, though instead of ending time it would cause rips in time instead, which fixing the paradox removes them.
IMO Time travel should work by usuable by people born with time powers, or people who posses a Time Stone, Chaos Emerald, Anarchy Beryl or or a device, automatically limiting people from abusing time control. Any character capable of obtaining these should be allowed to use time travel.
Time Travel works in a way that multiple of one person can be in one location at once. Say Bobby goes back to the past to stop himself from being pansted. He succeeds in getting vengence amongst the pantser and comes back to the present to discover the entire world in ruins due to the panster's severe case of F.O.A.I syndrome (Frequently Occuring Anal Inflamation). If he were to go back to the pantsing incident to warn Time Traveller Bobby not to pants the butthurt guy in retaliation, he would be able to do this with no reprocautions, AKA the universe wouldn't break a boner over the same person meeting their past self. After this warning occurs, that future never happened so the Bobby who saw the bad future would cease. Time Traveller Bobby would retain the information told by him (as time travelling devices, Time Stones, Chaos Emeralds ETC protect the user from time erases and pardoxes).
The only way for a paradox to occur is if two or more opposing events caused by time travel happen at the exact same time, thus creating a distorted future. At this point the paradox eats any future events that happened in the present/future and basically creates an End of Time. The only way to restore order and destroy the paradox is to go into White Space and destroy of all opposing events so that only one future may exist.
That's basically it.
Oh and only government and special groups should be able to create devices, all others must at least study a Gem to learn about time travel.
Apallo also suggested there should be a guardian of time but that'll go to whoever is the creator of the gems so yeah. Vote time!