I've done for-sale products in one day.

Supermodel Vickie took about 6 months, on and off.

SuperStar Vickie (who got through QA at DAZ yesterday) took just under 4 months of 40-60 hour weeks.   My first V4-based figure, so first thing I had to do was reverse-engineer everything, which added to the time.  She looks good though, doesn't she?  ;-)

Most of my products take about a month.