I would go back to the future.
I would use it to make sure that the last thing my late wife heard in her life was "I Love You".
I would travel to the cave man era and see what they went through to exist...
Of course the past lol everyone will say the past cause they dont know the future but when there in the future theyll be saying the past and today will be the past :O lol its scarey haha but good question though:D
Right..... so you have a time machine and you can use it only once. So I presume the whole stay in the present thing is to not use it as you'll be stuck where ever you go? guess like everyone else i'd head for the past, but i can't help but think about the whole paradox issue. Because what ever i change is likely to impact on me encountering the time machine later on the time line and therefore prevent me from traveling in time in the first instance. Damn all that Sci Fi....lol
Here is one to wrap your head around.....suppose time is not linear like you said and is more like pages in a book...separated but similar. When you would travel forward or backward relative to your perspective all you are doing is going from one universe to another.....avoiding any paradox. A multiverse in infinite dimensions. No need to worry about causality.......Sci-fi and reality can become blurry.
i would use it to travel back in time to prevent myself from meeting my current partner. as much as i love them their choice to change gender 3 years into our relationship is destroying me. i would have been far better off had i avoided meeting them in the first place. pm me if you ever get that time machine up and running, i'd be interested.
id go back 10yrs and stop someone from making a mistake
I'd go back to my past.