to be sure that you know what the time is, so that you finish sth at the correct time, or are not late for sth :
I'll have to watch the time. I need to leave early today.
to be sure that you know what the time is, so that you finish sth at the correct time, or are not late for sth :
I'll have to watch the time. I need to leave early today.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005