Must, have to, should, ought to
1.
Should (not) + whole verb if you think something
should (not) be needed. You give advice or advise against something.
2. must (not) + whole verb if you think something must (not) happen. More powerful than should.
3. has to / have to + whole verb to express certainty, necessity or obligation. Something is required by someone (else)
4. don't have to / doesn't have to + whole verb something is not required, it is not an obligation.
5. ought to + whole verb to give advice or of something should be done. This one is very formal.