The paper provides considerations relative to the application of 3D vision methods and presents some lessons learnt in this respect by presenting four 3D vision tasks and discussing the selection of vision sensing devices meant to solving the task. After a short reminder of 3D vision methods of interest for optical range imaging for microvision and macrovision applications, the paper enumerates and comments some aspects which contribute to find a good solution. Then, it presents and discusses the four following tasks: 3D sensing for people surveillance, measurement of stamping burrs, sorting burred stamping parts and finally, hole filling algorithm.