I use 2 family size bags for a half gallon. I put about 4 cups of water in the pot, ad the 2 bags (I pull the tags off and tie the strings together at the end and loop them around the pot handle so I can pull them out easily). Bring the water to a boil and let it boil for 5 minutes or so. I add a tiny pinch of baking soda to it to keep it from being bitter (add it after you take it off the burner so it doesn't foam/spill over. Take out the tea bags; add the sugar to the hot tea if you are using it, stir til dissolved. I make unsweet now, but before I used around a cup. I let it cool some then pour it in the pitcher. If it looks like the tea bag busted, i will strain it when pouring it in the pitcher. Add ice if you have it or just water to bring it up to the half gallon mark.
I like Luzianne Decaffeinated best, but I also like Lipton Decaf (that's what I mother uses). I also will use Food Lion store brand decaf. I don't really care for Tetley, and I loathe JFG (it tastes bitter no matter what). I keep it until I finish it or until it tastes sour. To me, sweet tea tastes best if you make it the day before you need it. We always made it on Saturday for Sunday dinner.