The objective of this treatise is to identity why estimators make certain common mistakes when compiling estimates. Estimators should educate themselves on what resources are available and how to use the available resources before they undertake the responsiblility of compiling estimates for companies operating in the construction industry. Resources like plant, labour, materials and applied markup form the basis of a rate. Estimators should have enough knowledge on how to use these resources before an estimate is compiled. Estimators that lack experience and knowledge regarding the usage of resources are dangerous estimators. Companies rely on their estimators to not just win tender bids but to also provide a price that the project can actually be constructed for.