It depends on how you’re planning to peek. Generally you’d want to smoothly track edges to clear out everything, including off-angles. Only if you’re quite certain of an enemy’s position you’ll “aim at the wall”, then peek out. Your cross hair will then be spot on immediately. This method always runs into the risk of overpeeking and getting killed easily. Smoothly tracking edges has the risk of getting swung out wide on, instead of getting peeked at tightly, such that sometimes you want to place your cross hair a bit away from edges, but only if you’re the one holding an angle statically.