Silicon Photomultipliers (SiPMs) are slowly but ubiquitously substituting PMTs wherever detection of low-intensity light is needed. In this talk, using DarkSide as case study, I will show the whole R&D flow, from requirements drawing to noise characterization to signal amplification and readout. I will shortly describe the challenges of SiPM arraying and the strategies to work around these. I will finally show how these SiPMs can be used to upgrade the current L200 veto or, possibly, enter the official L1000 design.