I have heard a number of students complain to their sensei lately. The general topic of these complaints has been "you MADE me learn this one way, and now you changed it."

Well, Sunshine Things... Change (Everything changes and nothing stands still - Heraclitus of Ephesus around 500 BC)

Now, do not get me wrong. Sometimes instructors make mistakes and a well-placed question can bring that mistake into focus. But far more often change is deliberate. When your instructor changes how you do things it is usually for one of several common reasons:

• You were doing it wrong in the first place and he just now caught you at it.
  
  I see this a lot because students are lazy; if you want more height to your side kick (yoko geri) then you can either:
  • Stretch hard, work hard, improve your flexibility and increase your muscle strenth (a lot of hard work); OR...
  • Drop your knee, roll your hip forward, turn your shoulders away and perform a kind of half-baked back kick you call a side kick
  
  Needless to say, most students take the second route and then go "Hey, look how high I can kick now!". Then they are upset when their sensei changes it.
   
• You were taught to perform a certain way because you physically could not do the technique properly. Ever see a baby who just learned to walk? Smiled at the stiff-legged, stumping, falling forward gait that almost always ended up back on hands and knees? Yeah, you used to walk that way too. Because you could not do anything else.
  
  Sometimes you are taught to do things the "baby way" so that you can learn a better way further into your training.
   
• You were taught to perform a certain way because the technique served a different purpose then. For example, I am questioned from time to time about the long stances taught in shorin ryu and shotokan karate, also in taekwondo. Typically this comes up when the lower ranked students are using these stances but the dan ranks do not.
  
  The reason for this is simple: Forcing beginners to use long stances makes them stretch. It also makes them align their bodies properly and causes them to build muscle strength in the legs.
  
  Experienced pratitioners use shorter stances more like what is seem in other styles because they are looking for mobility, stability, speed and tactical position. They should already have developed minimum strength and flexibility standards.
   
• Sometimes, your instructor simply learns a better way to teach. Or, needs to take a different approach to how they are teaching you.
   
• Sometimes, the way that your particular art form is done changes. All martial arts, including the koryu, are a constantly evolving living entity.

I guess the whole point of this is "change it had to come; we knew it all along" so embrace change. Learn a different way; do not get hung up on "what we always did".

And please stop whining about change;

the whole purpose of a martial art and/or martial way IS changes.