One hour time limit

Why do we have only one hour to edit posts? What's the reason for that? If I wanted to correct something and it's been 61 minutes, I can't. Why?

I know you can ask a Mod for help after the time limit. But, the Mod has to agree to the edit. Why? It's my post.

I wish we could edit too. Just in case I have to change what day I'm in and can't repost ad.

Because that's how the owner has set it up. An hour is more than enough time to read what you wrote and correct what needs to be corrected. If it was left open longer people would continually edit and/or delete their posts. Forums, therefor, would make no longer make sense. The owner and administrators believe if you write it, you own it.