It is such an easy skill to lose if you don't keep it up. I am kind of fortunate in that I have to teach it every year as part of IBTS Training.(individual battle tasks standards) I have no other choice but get into the books so I don't look like an idiot teaching it to the new guys. Especially the young Officers. Damn these folks are thick. You have to dumb it down to a 5th grade level for them.

(Insert long winded rant about new officers here)

Teaching it to others always forces a person to be extra careful and I find it an excellent way to remain up to speed. You will find it all comes back very quick and you will be teaching those cubs and scout 1,2 and 3 point resections and intervisibility in no time flat.