My girlfriend suggested that this information would help many people, even those who don't hire me (I assume it is because you don't live in the area, so I forgive you).
In my 5 1/2 years of experience, I have found that a small, one-person, studio apartment move can take anywhere from 30 minutes all the way to 4 hours, all with the same amount of total stuff.
It all comes down to preparation.
Step 1: Pack everything in advance!!
Do not pack just the "main things" - literally everything that you don't need to use the next morning should packed (at least) the night before; otherwise, expect to be making extra trips on your own to get all the little stuff.
Any furniture which will not fit through the door or down the stairs (i.e. bedframes, large tables with removable legs, etc) should be disassembled in advance.