had better

1 We use had better \o give advice, or to tell people what to do.
The meaning is present or future, not past, but we always use had, not have.
After had better, we use the infinitive without to.

• It's late — you'd better hurry up.
  (NOT . . . you have better . . .)
  (NOT . . . you had better hurrying/to hurry up.)

We make the negative with better not + infinitive.

• You'd better not wake me up when you come in.
  (NOT You hadn't better wake me . . .)

We can 'tell ourselves what to do' by using I'd better.

• It's seven o'clock I'd better put the meat in the oven.

2 We do not use had better in polite requests.

• Could you help me, if you've got time?
  (NOT You'd better help me. This would sound like an order.)