User blog comment:Fistful of Force/Fid support guide./@comment-9606680-20131014220926/@comment-3565549-20131014225457

Actually, depending on your style of play you don't have to buy a single pink for the entire game. You don't need complete bush control if you are playing a lane like janna + cait vs nami + ez, and you can just buy an oracle for mid game.

The point of pinks is to have complete vision control over a single bush/area, such as the tri, or dragon, say if you want a gank, or want to do dragon. It's sufficient to be able to "Know what's going on in that area", rather than to "Stop the enemy from knowing what's going on".

You can use this to your advantage too, if you are winning the lane hard and they pink the tri to clear out your ward: Get ready to be ganked.