[ziddoap]

When I was taking a Construction Engineering Tech degree (fancy name for quantity surveyor) this was a guiding principle of many of my teachers.

Estimating as a General Contractor is quite intricate. You're soliciting quotes from surveyors, excavation crews, concrete crews, forming crews, electricians, plumbers, masonry, flooring, structural, etc. There is a lot of things that go into a building to make it functional.

So, given that you have X amount of time to produce a comprehensive, profitable quote - you really have to manage your time. If you spend all your time counting the nuts and bolts on a project but forget about the 3rd floor framing, you're going to go bust pretty quickly.

The solution is to apply this principle. Focus on the 20% which will give you 80% of the cost. The big ticket items. If you have time, fill in the rest of what you can.