Cleat wear -- perhaps swapping the left and the right would rule that out (I know I wear out my left cleat so much faster than the right one -- as the result of a heel injury, I unclip with the left even though my dominant leg is the right one)

Insoles: I am using eSoles in my Sidi shoes -- you have a choice of three arches and metatarsal support. I used to have a Specialized insole before. I like both products.