There's little minimizing the bodily wear that an aftermarket ATV steering stem kit can save taller riders, to say nothing of the instantly felt difference in comfort.
Gaining a proper steering posture at the standard height of many machines' OEM bars often forces riders over six feet especially to adopt an uncomfortable and unhealthy bent-over position. Holding this less-than-ideal form at length and trying to compensate can sap strength and endurance from the neck, arms, shoulders and upper back over the course of a long day's ride. The ensuing fatigue can create competitive performance issues among competitive riders and take a notable degree of enjoyment out of a casual rider's day with ever painful twinge and muscle ache.
Modifying your machine with a +1 (1") or +2 (2") ATV steering stem kit can open up a world of difference in the form of longer, more comfortable rides and even smoother handling. That inch or two could transform your riding posture and balance from a Quasimodo hunch to a more balanced, steady upright position. That being said, your swapped-in stem has to effectively fit your ATV's body as comfortably as it suits yours.
Incorporating an aftermarket ATV steering stem kit may demand some peripheral mods to adapt your machine's performance to its changed dimensions. You may need to switch to longer brake lines and clutch cables, depending on your ATV's particular bar-bend.
An adjust steering stem can even benefit "average-height" riders, in some instances. An ATV with an over-sized gas tank can create the kind of unbalanced riding geometry that a +2 stem kit can effectively offset.
Few things bear out a machine's comfort quite like riding it through its normal paces. Ideally, riders should perhaps take a friend's ATV with a longer stem out for a ride in order to gauge overall comfort, differences in pullback, and whether an extended steering stem might dramatically alter arm-pump during the ride.