It’s also important to remember that techniques sometimes need to change when situations change; it is up to you to learn or relearn what you need to know in order to maintain mastery of your chosen discipline. For instance, a Green Beret of the Army Special Forces must be highly proficient at transitioning from their rifles to their pistols as rapidly as possible in case their rifle ran out of bullets or malfunctioned.
A Warrior is flexible and knows how to improvise, adapt and overcome.
A retired service member proficiency in this skill is no longer necessary because they don’t carry a rifle all the time. However, they might carry a pistol. The physical act of drawing a pistol from a concealed holster is much different than drawing from a leg holster, so you have to train and adapt to this new technique. And by doing so will make you proficient and lethal as had before while in the military.
Remember: You can’t just rest easy and expect skills to stay with you for life because you knew how to do them a long time ago. You should continue to practice, modifying your technique if necessary, no matter how good you are in any given discipline.