When "shifter shine" starts to turn to shifter hole.
Do you really shift with your foot that far under the shifter? I shift with the end of my boot near the toe, not way up on top of my foot.
Bikes are as different as human physiques, BB. Depending on the boot I'm wearing on that trip, and the bike itself, my shift place will change. So will everybody's. Just because my normal shift point is at my mid-big-toe joint, don't mean it's wrong if my buddy shifts with his boot tip, top of his metatarsals, or the side of the sole. Don't matter. Y'hear? don't matter.

But dont' forget to get that boot out from under the shifter in the twisties, or you'll grab that foot and it will go right under the bike. Darn near broke my left foot on Deal's Gap, I felt so dumb with my bruise for a week after that....