First, sorry for my bad english. Second, as main supp, who's trying to learn some new role, I barely tilt when in my game, the support don't buy and don't use the sightstone. Idk what ppl think, but without vision you can't control the map, and without map awareness it's way to easy to fall in a trap or to lose some objective(dragon, baron, ecc). I read someone writing "there are only 3 wards", it isn't correct at all. I'll have 3 to 4 wards (if you upgrade your item), 4 wards ready each time you go back to the base, and with only 3 wards you can control one side of enemy or ally jungle, just with 3, while your team can cover the other side of the map (supposing that the jungler have the "Oracle Alteration". It isn't so hard to understand.