A bad habit
I overheard a friend telling his pal, "I can't break my wife of the habit of staying up until 5 in the morning.""What is she doing?", the pal asks."Waiting for me to get home."

A precise location
Attorney to witness: "And where was the location of the accident?"Witness: "Approximately milepost 499."Attorney: "And where is milepost 499?"Witness: "About halfway between milepost 498 and milepost 500."