We have identified a correlation of increasing albedo for increasing phase-function slope using ground-based and spacecraft observations of 14 Jupiter-family comets (JFCs). This can be interpreted as an evolutionary path of JFCs, according to which dynamically young JFCs start their evolution with relatively high albedos and steeper phase functions. During their lifetimes, sublimation-driven erosion gradually makes their surfaces smoother, and their phase-function slopes and albedos decrease. If confirmed, this correlation will provide a compelling opportunity to study the surface characteristics and evolution of JFCs from the ground. We have therefore designed ground-based observing programs which aim to validate the correlation and to study its nature. We will present the results from our observing campaigns in 2018 and 2019. We will also discuss the results of our effort to compare the surface properties of JFCs to those of Centaurs and dormant comets in order to check the validity of our evolution hypothesis for the different evolutionary stages of JFCs.