Keep tab - Idioms by The Free Dictionary
https://idioms.thefreedictionary.com/keep+tabkeep tab keep a tab on (someone or something) To routinely monitor or observe someone or something; to keep track of someone or something. It was revealed that the FBI had kept a tab on him for years due to his political activities in college. Please keep a tab on the amount of feedback we get so that we know how many people this issue affects.