To remember with concern; to keep thinking about or worry about someone or something.

to constantly have someone or something on one's mind; to be anxious or concerned about

less worried about being robbed than about a thief having their sights set on you; it is more dangerous when someone is constantly plotting or waiting for an opportunity to do harm than the harm itself (idiom)

to be excessively calculating or concerned with small advantages; variant form of a phrase meaning to weigh and measure every little thing