What time do postal workers get to the post office?

do you know what time post office workers get to the post office? I know when it opens but the workers must get there early. my brother dropped off a envelope and has to retrieve it. I told him to be there right when the postal workers get there but I have no idea when that may be..........any guesses?What time do postal workers get to the post office?
The ones who get there before the customer service window opens have been specially trained to ignore you.

That being said, the carriers and supervisors tend to start anywhere between 6:30 and 8 am, clerks and mail handlers show up even earlier.What time do postal workers get to the post office?
About half past murderous rampage o'clock.What time do postal workers get to the post office?
Um....you answered your own question. Postal workers arrive to work between 4a.m. and 5a.m. but it doesn't mean their doors open. You can't retrieve a letter. Say you drop a letter off in a blue box at 4p.m. That same day at 5p.m. the blue box is emptied and the process for shipping has already begun.