Originally Posted by iridehorses
I never subscribed to that rule of thumb. I always place my bits so that they are just touching the corner, never so tight that they are pulling my horse's mouth back - never could figure out the reason for the "smile" or "wrinkle" rule.
I second this. The reason I was given though, for why there should be wrinkles, was to ensure that the bit wasn't hitting the incisors. However, there is a much more reliable way of checking that, and that is to bridle the horse, then pull the lip back and see where the bit is sitting
. I've never had to have wrinkles on any horses I've tacked myself, except one, and it was only 1 wrinkle then, not 3 as we're so commonly told to do.