Expressing advice : had better

(a) My clothes are dirty. I (should/ought to/had better) wash them
(b) You’re driving too past! You’d better slow down.
Had better has the same basic meaning as should and ought to:”This is a good idea. This is good advice.”
Had better usually implies a warning about possible bad and consequences. In (b): If you don’t slow down, there could be a bad result. You could get a speeding ticket or have an accident.
(c) You’d better not eat that meat. It looks spoiled.
Negative: had better not
(d) I’d better send my boss an e-mail right now.
In speaking, had is usually contracted:’d

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