Leeching isn't frowned upon on this site so don't worry about it. The admins are not going to shout at you.
It is nice to seed and the suggestions I have seen is to allow a seeding to continue until there are a few seeds available. Especially if it's a new torrent and popular. I have also seen posts saying to stop seeding if there are a lot available to save on bandwidth.
I would suggest that if it's not a popular torrent there's no point in keeping it seeding but keep a watch on the "torrents needed" box on the index page and, if you have it, start seeding it. You should be able to just "stop" a torrent without removing it from your list.
I'm sure one of the top guys will give you the official line.
Personally, I like to seed as much as I can but I still have many with a zero share ratio because nobody is asking for them. As they remain on my PC, I can't see the point in not making them available if required.
Oh, if you like downloading from here, may I suggest an external hard drive - the largest you can afford?
That way, it doesn't take up room on the PC. I have several - mostly for my Disney stuff (those HD videos do eat into the hard drive)
