#1 Long-term success
Jose has used the transfer windows until now to shape this United team according to his liking. The spine of the club has been formed entirely from his signings as the Bailly-Pogba-Lukaku backbone that runs through the pitch is a setup for the long term.
Apart from Zlatan and Mkhitaryan, all other Mourinho acquisitions look like they are here to stay for a number of years.
After the debacle under David Moyes in 2013-14 and the lethargic game they played for two seasons under Louis Van Gaal, United need Mourinho to stay for a long time in order to get the club back to winning ways. With a young set of players working under his tutelage, Jose is well placed for the success he craves at United.
Also read: 5 things Manchester United are doing better under Jose Mourinho