Estimating Project Times and Costs Without Losing Your Shirt--Or Your Sanity
http://www.geoff-hart.com/resources/2006/estimating.htm

Hart, Geoffrey J.S.
Geoff-Hart.com
2006

Abstract:

Determining how long it takes to complete a job is essential for planning and for budgeting your time, whether you're a wage slave or a freelancer. In this article, I'll focus on the needs of the freelancer, but the same approach will work equally well for managers of teams of technical communicators and even for lone writers.