Hi hypa2sick,
Even if there are providers you don't currently need it can't hurt to leave then running.
For example, I don't do any file sharing but my P2P Shield is active anyway. This way if I ever decide to do some file sharing, or if another user sets this up on the computer without telling me, I'm protected without having to remember to activate the shield. I don't think I would see much difference in system speed by turning P2P Shield off, anyway.