The present disclosure refers to servicing printing systems, wherein the system comprises a controller to: instruct an ejection of printing fluid from each of the nozzles within a printhead; detect, by a drop detector, drops ejected from each nozzle; determine by the controller a drop time for each nozzle, being the drop time determined between the instruction of the ejection of printing fluid from each of the nozzles until the drops ejected by each of the nozzles reaches the drop detector; and determine a nozzle health parameter in view of each nozzle drop time; wherein the method comprises comparing each nozzle health parameter with a threshold value and instructing, by the controller, a servicing operation if the nozzle health parameter is outside a threshold range.