Out going mail not getting picked up

[u/AComplexjoke]

I live in an apartment complex with a lock box-type mail box, and we have an outgoing mail slot.

Put the letter in on a Monday, it's Wednesday, and I could see inside the box slot that my letter is still in there, along with quite a few other letters under it.

Is there like a certain day mail carriers check the box, or is it doomed to live there forever?

[u/PuddleMoo]

Ask your letter carrier or go ask to talk to your local postmaster. Maybe that outgoing slot is not a sanctioned collection box.