Distributed Fiber Optic Sensing (DFOS) covers several technologies that each utilise fiber optic cables to provide measurement of different parameters: Distributed Temperature Sensing (DTS), Distributed Strain Sensing (DSS) and Distributed Acoustic Sensing (DAS). For leak detection, DTS and DAS are the main DFOS technologies that are available. There are a wide range of variables that define the appropriateness of DFOS technology for leak detection and it can be difficult to decide which technology should be implemented. Aside from the simple scenario where one or both technologies are not suitable, the ideal solution would be to install both DAS and DTS. However, this is often undesirable for cost reasons. We will discuss the main capabilities of each technology and the parameters that determine the suitability for different pipelines. We will also give our view on the most appropriate technology for leak detection on some common pipelines, including examples of operational deployments.