How much can a user delete on their own?

Sometimes a site has a user that just wants to delete all of their post. For the last few days I have been watching a user that had a few hundred post slowing deleting their post. But I noticed that they have not been deleting the post they started, i.e. OP.

So I was wondering just how much a user who wants to vanish can do so on their own?

NB I have admin rights so I can see the exact count change on the days they are deleting.