Medical and training facilities are my priority because of the boosters.
Academy i only upgrade after reçeiving my youngsters and whend i am sure the youngsters Will arrive in the first days of New season, to do that you always have to do the math, 3 contruction days, plus the number If day for them to arrive.
Pitch is also a priority.
Stadium keep upgrading seats, because each level have a maximum atendance, so you do no need to have a number If seats higher that the maximum atendance.