How often do you use "F lock" and in what situations? I'm thinking that it's for when you are "in deep" and need to pull every bit of traction to get yourself out.
F-lock or Diff lock just locks both front axles to the carrier so there is no differential. Should only be used when going straight as possible as steering is reduced and more stresses are placed on the pinion,case and CV joints during turning...never the less, it used when you want or need all four wheels to have the same traction such as in some mud situation, hill climbs on softer stuff, some snow situations and with care, rock crawling. I almost never need to use it in a normal trail ride.