I would renew Terry's contract as long as he wants to play here without a second thought. Terry will know when his time is up, he wouldn't carry on playing if he didn't think he could do it anymore.
It should be Terry's decision when he wants to leave the club. After everything he has given us fans, this should be his choice.
The only other club that treats their greats in a similar way is Real Madrid, it's one reason why football fans see them as a soulless club.
Terry is more than just a footballer to this club. It's not just on the field that he has been great, behind the scenes he has helped the club greatly.
We aren't talking about just one of our legends here, he is our greatest in our history. No other club would do this to their best ever.