6+ year old...I would not mess with the anode nor the T&P at this point. Check it once a month, when you see rust starting to appear around the bottom pan of the skin, time to change it out.

If you have a WH with a plastic drain, I would pull it, let the water drain out, replace with a brass one. While it is out, rent a scope from HomeDespot and look at the anode through the open port.