For contract work in general, both technical and non-technical, the answer really is "it depends."

Sometimes a company really does need something yesterday and you're the bottleneck in getting something released/getting revenue/etc. Bit I've taken on writing and video projects for example that were components of a marketing campaign that was scheduled to launch some months down the road so it was a pretty part-time thing. Mostly I've worked on internal projects but the same principle applies.