I'm imagining a world where time travel is a part of day to day life. Technically speaking, a sealed chamber (imagine it being about phone booth sized) would be linked to it's past and future instances of itself. This gets around issues like "the Earth is moving through space so if you travel to the EXACT same space in the universe you won't be on Earth you'll be floating in the cosmos" because instead of being in the EXACT same space in the universe you'll be in that chamber wherever it is.
There's no affect of constant time traveling other than extreme instances of "jet lag" (time lag?). There aren't diseases or ailments that arrive from over use.
Anything within the chamber is moved through time with the person, air and all. To facilitate this, the "receiving end" of the time travel jump needs to be a vacuum. Cargo can be sent without a human passenger as the chamber is operated by somebody outside of the chamber.
Given that the machine is functioning normally without any damage, it's safer than a flight by today's standards. However, a collision could occur when time is mismanaged and two people exist inside the chamber at the same time (whether it be somebody arriving just as another is departing or that two people arrive too close to the same time). This kind of collision usually results in the death of the people or at least destruction of property if only cargo is transmitted due to overlapping atomic structures and increased pressure of the chamber (there's 2 chambers worth of matter in the chamber at the same time).
There are public stations similar to today's bus stations or airports where the public can travel time if they've bought a ticket. Time keeping is kept very strict to prevent collisions in the chambers. There are also private stations operated by businesses or governments for their own uses.
What kind of laws or restrictions are there that would help reduce paradoxes? How might the people in charge of the stations organize arrivals and departures when arrivals could come from either direction (forward or backward in time)? How might individuals and workplaces use time travel? I can imagine a research company repeatedly looping their scientists so they re-live the same day over and over to produce results from their research (relatively) faster in the grand scheme of the timeline. Are their personal uses for time travel? How can age be regulated? Being born in the year 2000 but spending 20 years of your life repeating 2007-2010 for a job or some other reason means that in 2011 you're not necessarily 11 years old. Other than fear, would their be any reason to avoid time travel? How is the economy impacted if goods can be jumped in from a time when their production was cheaper?
Ultimately this comes to one question: how can cheap, safe, easy to use time travel be used, governed, and managed?