From Longman Dictionary of Contemporary Englishhad betterhad bettera)ADVISEused to give advice about what someone should do, or to say what you should do or need to doI’d better go and get ready.I think you’d better ask Jo first.You had better not tell Oliver (=it is not a good idea).b)THREATENused to threaten someoneYou’d better keep your mouth shut about this. ► In speech, people usually shorten had to ’d, and may not pronounce it at all. But do not leave out had or ’d in writing: You’d better (NOT You better) come here! →better
Examples from the Corpus
had better• I'd better not go out tonight; I'm really tired.• You'd better phone Julie to say you'll be late.• I did not want to go, but Dana said we had better do as they asked.• But Walter is a poorshade of what we have had better done.• They told Weary that he and Billyhad better find somebody to surrender to.• I realized I had betterhustle him out of there before he was asked about his actingcareer.• Any organisation dismissing that vision as science-fiction had better look out.• In April 1911, he seemingly had betterluck.• He thought he had better reread that part of the book.• After what he has now said about a referendum, he had better watch out.