Free: Contests & Raffles.
No you do not but turrets are a much better way to go. You don't have to count clicks. Also you don't have to look at a sheet or carry a card. All the info is already on the dials. So you just have to judge wind and turn your dials.
I am using the LR. All 6.5-20x50. Tough to beat that scope. I have NF as well, but the Leupold LR is much lighter than the NF. A plus on some of my mid-weight rifles.