Something to say about number of files per folder is.
A lot of hosts will limit how many files per folder. Or at least used to.
Meaning you have say 15000 files but when you ftp you only see say 9000.
With that said I have always asked that we have the option when setting attachments or any uploaded file locations to be able to add multiple folders and set limits to each folder.
A couple of other vendors allow this.
SD had a good idea on pic upload that did just that.
As well as it auto created folders based on the month/year uploaded.
So you never exceeded that limit.
But it was discovered for other reasons that the mod had some modern security risks.
But the concept was still a good idea.
