Shaykh Salih al-Luhaydan explains that a traveller should shorten prayers only if staying less than four days. If the intention is to remain for more than four days, the traveller should perform the full prayers and not shorten them.
A person is visiting Saudi Arabia for a period of one month. Does he shorten his prayers for the duration of his visit?
That which is correct is that if a person intends to stay for more than 4 days, then he should complete his prayers and not shorten them.