SHOULD Brett Favre retire?

I know the question has been asked a million times, but I would like to see how peoples answers have changed now that the dust has settled. Now I put the word "SHOULD" in caps because you get know it alls that say "Brett IS going to retire". Thats not what I am asking. I am asking do you think he SHOULD. So here is my opinion. Now ask yourself when and why do people retire? Now most people in sports retire when they can no longer do what they did when the first started. Example? Boxers often retire when they get knocked out a few times. Basketball players retire when they just can't play like they used to. Etc... Now Favre just had his best Completion percentage he has had in a season and finished with a QB rating of 107.2. That was the second highest rating, second to none other than Drew Brees. Now why in the world should he retire? Now of course I say this not knowing how his body feels at the end of the day. However it must not hurt to bad if he came back again. What are your opinions?