We can also use Should you as an alternative to If you should in these situations by changing the order of the subject and the verb. Compare these two sentences with the examples above. They have the same meaning and they are also formal:
Should you wish to use the Internet, there is a code available at the reception desk.
Should you decide not to go on the trip, you will get a full refund.
In speaking, we often say you shouldn’t have when someone gives us a gift:
I got you something from Texas. A cowboy hat.
Oh Ken, youshouldn’t have!
Surprise or regret
We sometimes use should to express surprise or regret about something that happened:
I’m amazed that he should have done something so stupid.
I’m sorry that he should be so upset by what I said.
Should and would
We use should as a more formal alternative to would with I and we in conditional clauses.
I/We should love to meet her again if I/we had a chance.
I/We would love to meet her again if I/we had a chance.
We use should as a more formal alternative to would when we want to be less direct.
I should think that a lot of people will be interested.
I would think that a lot of people will be interested.
Should and ought to
Should and ought to have similar meanings and uses. Ought to is more formal and less common than should:
We should clean up the garden.
We oughtto clean up the garden.
Should is much more common in negatives and questions than ought to:
Should we keep a seat for Margaret? (more common than Ought we to keep a seat …?)
He shouldn’t speak to his parents in that way. (more common than He oughtn’t/ought not to speak …)