We've never had to schedule personal days in advance the same way that vacations are scheduled. We just put them in as a regular request the same way you would ask for any day off.
At our store currently, many people are taking weeklong vacations. So, we need everyone we can scrounge together to cover their absence. Summer madness is here.
My opinion is: Eschedule will not allow you to make requests 13 days in advance now that we went to the 2 week schedules. So, my answer is you only need to make the requests 14-15 days in advance. I do not ask for days off so correct me if I am wrong about the time limit.
It depends on your state and your union contract. Ask your shop steward for the correct answer for your situation. Ask them to show you in the union handbook where it says you have to request ph days off 60 days in advance.