Unlike new construction, repair and restoration work involves varied and unusual operations. Also, in many instances, neither the final design nor construction budget can be established before proceeding with at least some of the work. This is particularly true in major restoration where surprises almost always greet the contractors and designers once removals are commenced and the actual existing construction can be viewed.

Repairs frequently involve working in occupied structures or facilities. Often, continuation or resumption of normal use of the facility, during or after the repair, is of top priority. The time required for the repair, whether or not normal operations can continue during its execution, and the amount of interference created are often far more important to the owner than the cost of the actual work. The client in such cases is not really interested in how much money the contractor charges, but rather in how much he saves as a result of the contractor's knowledge, ability, and resulting job performance.