think twice about something/about doing something

think twice about someone or something

to give careful consideration to someone or something. Ed may be a good choice, but I suggest that you think twice about him. You will want to think twice about it.
See also: think, twice

(not) think ˈtwice about something/about doing something

(not) think carefully before deciding to do something; (not) hesitate: You should think twice about employing someone you’ve never met.If they offered me a job abroad, I wouldn’t think twice about taking it!
See also: something, think, twice