Always right front pocket, no exceptions.
Whatever my pocket knife of the day is, it gets dropped in that front pocket along with my Fenix E01 and one of the two bandanas I carry. Never carries. No matter what pants Ihave on, jeans, Dockers, dress pants, the bandana is loosely wadded up and shoved down on top of the knife. I have never lost a knife yet. Keys, change, tiny bottle of hand sanitizer, all go in the left pocket.
Always, always stuff that bandana down on top of your knife, and you will never loose it.
Carl.