I make a small hourly wage at a technical part-time job at a California startup. My father recommended that I work 5 minutes before and after my timesheet begin and end times, respectively, so as to, I suppose, refute the appearance of cheating. Is this practice normative?
This is very dependant on company culture (which may itself depend on the field and country you work in).
From my experience in IT (in France, but as far as I know this is the case in most country), people won't care or even notice a 5 minutes difference. Generally speaking the precise amount of time you spend at work isn't very important as long as you get the work done. It will however be very appreciated if you are - and most likely frowned upon if you aren't - willing to make extra effort when the workload is particularly important. That is, for example, just before a deadline.
Again, this is from my own experience. The best you can do is figure out how things work in your company, and act accordingly.
While I will be the greatest supporter of only working the time that you are being paid to I also operate on a similar rule in regards to a small buffer time, it's just a matter of professionalism.
You should be appearing 5 minute ( or so ) early to any job so there is never any question as to if you are actually in the office at the time you are supposed to be there .
Most of the time I will show up a few minutes early and go make a cup of coffee or have a smoke in a relaxed manner right out the front of the building . But the important thing is that when I am supposed to be working I am there and not rushing to travel in.