From my "limited" experience the performance side of the business seems very seasonal. Business seems to drop off during winter, at least around here. The ones that stay afloat have other means to make money to keep the lights on, like doing general repair work or manufacture their own parts/have a web business to fill in the gaps. Of course if you alienate your customer base or are bad with money this model won't work either. In that case you're generally fucked.