This article has been prompted by the number of support requests received from SQUEAC and SLEAC practitioners regarding the two different estimators of coverage (i.e. point coverage and period coverage, see definitions below) in current use. Both of these estimators can be calculated using data from any of the currently used coverage assessment methods (i.e. CSAS, SQUEAC, SLEAC, S3M) but often produce very different results. The SQUEAC and SLEAC technical reference encourages investigators to select and report only the most appropriate estimator, with the choice of the most appropriate estimator being informed by the context.