For me (after struggling with parts creation for coming up on a year with lots of help from the other folks in here 
), only an hour or so with Inkscape and the data sheet. To someone new to parts creation a lot more of a problem. Once you are up to speed, parts creation isn't bad, it just takes a lot of effort and mistakes to get up to speed. It helps a lot if you are already familiar with a svg graphics editor like Inkscape (which I wasn't, and after a year still aren't, it wins with regularity ) but even then fritzing has its share of things it dislikes that you need to trip over a few times
Peter.
Peter