Should Forum Members Be Able To Edit/Delete Their Posts?

I have a xbox forum & im not sure weither i should allow my members to be able to edit and/or delete their posts.
What have you got set on your forum?
Whats your thought on allowing editing & deleting posts by members?

The setup we have here is that members can edit/delete their posts for up to 30 minutes, after which they get locked down. That is plenty of time for people to check their posts and correct any spelling or BBCode errors, or to add anything they missed. The danger of allowing people to edit/delete their posts indefinitely is that they can then introduce spam links or other disallowed content a few days later, and you’re unlikely to see it – it can also lead to people changing their posts to make it look as though others are misrepresenting them, that’s how arguments and flame wars can turn nasty.

Yes, i was thinking that too… about members going back and changing topics after replies to make it look like another thing.
Currently i have it so my members cant edit or delete their posts. But i may just take up on whats on here. The 30 minutes to edit then no more.