>>19055
>Is there an expiration date for the uploads?
No.
>files pruned from the site after some time?
Orphans are pruned.
If all the posts with the same media are deleted, that creates an "orphan".
>How much is that time?
Within weeks. Kinda random.

>>19056
>>19057
There was a botched migration in 2018 or so which resulted in database corruption. There is a thread about it here on operate somewhere. The result were bunch of lost media, broken files, some just left without thumbnails.
Well, that's about it.