Recycle bin retention period: maximum days

I had the 70-668 PRO SHAREPOINT 2010 exam today and a doubt pop-up in my mind when reading a question.

It was related to how long a document could stay in the recycle bin. And I didn´t know the answer. When I tried to find some answer I couldn´t find it at Microsoft technet or at least I couldn´t place it, all what I found is:

·  You can specify a time after which items in the Recycle Bins are deleted, or you can specify that these items should never be deleted. By default, items are deleted after 30 days.

·  You can specify a percentage of live site quota for second-stage deleted items. The default setting is 50 percent. You can also turn off second-stage Recycle Bins. If you select Off, site collection administrators cannot recover items deleted from end-user Recycle Bins.The second-stage Recycle Bin quota percentage must be a value from 1 through 500.

http://technet.microsoft.com/en-us/library/cc287766%28v=office.14%29.aspx

So I tried to modified the default value (30) for a bigger one in "delete items in the Recycle Bin" After : 9999999999 and I got a message "Recycle bin retention period must be between 1 and 10000 days"

More than 27 years for retention.. nice number.

Moreover you might choose "never" also, which means that all deleted items will remain in the recycle bin until you will remove from there manually. This option may require extra management to avoid storage issues ...