Answer
This structure is most commonly used to make recommendations. It can also be used to express desperate hope as well as warn people. Whe we use "had better" there is a suggestion that if the advice is not followed, something bad may happen.
Ex.
You had better take your umbrella with you today. RECOMMENDATION
I'm terribly late for my flight! The bus to the airport had better get here soon! DESPERATE HOPE
You had better watch the way you talk to me in the future, yound man! WARNING
We normally contract this form when talking, if possible: You'd better take! You'd better watch...
We use "had better" to give advice about specific situations, not general ones. If you want to talk about general situations, you must use "should".
* You should brush your teeth before you go to bed.
* I shouldn't listen to negative people.
* He should dress more appropriately for the office.
Anyway, the form "should" can always be used, whether for general or specific advice