Howdy, quick question on the subject of leechery.

If I download a file but it's not what I expected or I've listened to/watched it and am done with it, how long should one keep it shared before deleting to be polite and not be considered a leech ?

Obviously one needs to be sure it's there long enough for at least one other person to grab a complete copy (otherwise the availability of the file would shrink to zero over time), and ideally (in the land of infinite disk-space, that is) it would be kept shared indefinately until every gnut had a copy of everything gnutworthy.

However, human nature as it is, some people will cheat a bit on the deal. If only one in three users 'plays by the rules' it's necessary for them to keep downloads shared until at least three other users have a complete copy (one of which on average will be shared, and so the gnut-space doesn't shrink and the universe is happy).

So, to my initial question, how long should a good gnut keep a file available for upload once downloaded ?