I currently work 8 to 5, more or less. Most of my co-workers do the same and leave at 5. However, I want to switch to a 7 to 4 work schedule or something earlier so that I can get home earlier.
Our start/end times aren't really monitored, people set their own semi-flexible schedule, as long as you do your standard 8 hours. My concern, though, is that if I make a schedule change and suddenly leave an hour or more earlier, my co-workers might start to think "Gee he's leaving so early, he must be slacking off". My boss won't be an issue, since he also starts and leaves earlier; it'll mostly be the other co-workers gossiping if anything.
I'm also fairly new to the company so I don't want to be seen as the guy who slacks off.