Quality assurance and testing before, during, and after construction of semiconductor tracking detectors

We discuss the most frequent problems met with during the construction of three generations of microvertex detectors and a silicon-tungsten luminometer for the OPAL experiment, and during the many small projects and R&D work for other experiments and university projects. The emphasis will be on describing technical details and work practices adopted to prevent damage to and loss of expensive material, and the techniques preferred to prevent disaster during construction.