Had better/best do something - Idioms by The Free Dictionary
had better/best do something
had better (do something)
Should. You had better listen to what I'm saying before you get yourself into more trouble.
had better/best do something used to tell somebody what you think they should do: You’d better lock the door before you leave: there are lots of thieves about. ♢ Hadn’t you better check to see if the baby is all right? ♢ ‘Shall I phone her now?’ ‘You’d best not. She might be asleep.’