We use should

• for a strong suggestion.

EXAMPLE: You should go back to him. (It's not a 'must' but it would be good to do so.)

• for advice and recommendations.

EXAMPLE: You should not be going now. It's going to rain anytime.

• for something that is right or morally right to do.

EXAMPLE: You should cut down on your heavy drinking.

• when something is not right or normal.

EXAMPLE: They should be queuing up

• for something or something fair to happen.

EXAMPLE: She has been shoplifting, so she should be caught.

• for the present moment.

EXAMPLE: You look tired. You should go to bed now.

• in place of ought to. (No difference in meaning here.)

EXAMPLE: I think you should/ought to make more time for yourself to relax.

• with if.

EXAMPLE: If Jane should come while I'm out, please tell her to wait.