The manner in which electronic nicotine delivery systems (ENDS) are used is a strong determinant of real-world emissions and, as such, may impact user exposure to chemical constituents. Information on puffing topography is therefore important to facilitate evaluation of machine yields from ENDS to estimate exposure from conditions reflecting actual use. In February 2018, the Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) published it's "Technical Guide for the Selection of Appropriate Intense Vaping Regimes for E-Vapour Devices”. The review recommended factors to consider when determining puffing parameters to use for aerosol generation under an intense regimen on smoking/vaping machines to facilitate assessment of chemical constituent yields. The literature review which underpinned the CORESTA recommendations was limited to papers published prior to and during 2016. Since that time, a number of studies involving human subjects have been published containing puffing topography data from both ambulatory and laboratory studies, and on a wide range of ENDS types, such as open tank systems and closed systems such as cig-a-like and pod systems. Furthermore, several studies have examined the relationship of ENDS parameters - including power output, liquid components such as propylene glycol/vegetable glycerin ratios, and the presence of flavour ingredients - and puffing topography. This presentation will provide a critical review of the literature published since the drafting of the CORESTA review and will discuss how puffing topography varies between different ENDS types and the association of device parameters with puffing topography. Furthermore, the presentation will review the associations of e-liquid components with puffing topography. Recommendations for appropriate puffing parameters to use in aerosol generation for analytical purposes will also be presented.