In general, most people's honest estimates are lowballing it. :) Seriously though, you want to give an honest estimate. What helps at the sales stage is provid

In general, most people's honest estimates are lowballing it. :) Seriously though, you want to give an honest estimate. What helps at the sales stage is providing _context_ for the estimate. In other words, don't just quote a figure, break the job down into a project plan with time/cost estimates for each section. When I was consulting and going after large, somewhat ill-defined projects, I found it was often possible to sell the client on a short (1 to 2 week) engagement to look into their problem, drill down on the unknown bits and make them known, and deliver them a project plan and a set of time/cost estimates that they could then use to better solicit bids. Yes, we usually got the development work on those gigs, but it was a separate project.