I know I'm just the local school bus fanatic, but time travel and the like facinate me.
My personal uses for time travel would be to observe historical events that catch my interest, primarily milestones in the Space Race up to the loss of Columbia in 2003.
Pratical uses, however, I see some lunatic changing the course of history or some wannabe "hero" completely mucking up the time line.
On that note however, I'm also one who believes that for ever possible course of action, a reality with that outcome exists. So the alteration of the time line, in how I believe, would result in the person returning to the altered time line, much like how Back to the Future II and JJ-Trek played out. There exists a point of intersection for the two time lines, but everything beyond that point is altered, thus allowing someone from Timeline A to exist in Timeline B.
But that's two cents worth of a bus's take on temporal mechanics on time travel.
That's pretty much my thoughts on it, and with my situation, I'd just like to change lines
There is good news and bad news about Time Travel.
The good news is you can go back as many times as you want and "mine" the past for things, even duplicates of the same thing, without any repurcusions to "your" timeline.
The bad news is that you would have to remain in the past timeiline you visited if you want to see any repurcusions ie: removing someone to improve the world will only effect that timeline. When you go "Back to the (your) Future" your timeline remains uneffected.