Recently I had someone ask me if learning martial arts for so long makes it easier for me to pick up a new style. His thought was that developing different muscles through time would allow an individual to pick up another style faster than the average person. I'd have to say this is unfortunatley for me never really the case. Granted if the style that you are changing too is related to the previous style you study such as Taekwondo to Hapkido. Then the transition is very smooth because all of the ideas are the same but Hapkido provides more movements. However if you have learned Ninjitsu and are transitioning to Wing Chun then it can actually play against your learning. Its the same as a gymnist switching to swimming. Even though he is used to exercise and hardwork he will still have to make a major adjustment mentally before understanding the new movements. He will even have to untrain some of the muscles that now are a hinderance. When I first met my master Wu Guo Zheng I had already been training martial arts for twenty years. But when he had me doing the new stances my legs were so tired that they began burning and shaking like never before. I used to pretend I had to go to the bathroom to make the pain stop. Until of course he asked me, "Why do you go to the bathroom every time you start to learn?"
I think the most important factor is having an empty mind. It seems like something that we hear all the time in the martial arts world. Yet it is something that expereinced martial artist can not do easily. I admit there have been times when I was younger that I would come into a new dojo thinking, "I already have my black belt in two other styles, this should be easy to learn." It is that very thought that restricted me from understanding the new philosophy that the master was trying to teach. If you use the same kick from Muay thai, kick boxing, Tae kwon do, Ninjitsu or whatever, it may appear the same from the outside. But on the inside the concepts are very different for reasons of power, speed, stealth, evasion etc. If you see your teacher do a kick that you assume you already know, then you have missed the whole point. Now you have become too smart to learn and this is where your training will plateau.
An open mind means that you have to completely forget that you have learned anything when you step into a new classroom. Even your thoughts can make you miss many points of the lesson. After you leave class you can begin to compare, contrast and research your other knowledge. Simply put, humility is the path to power.
It does pay however to be mindful of who you are learning from. Anyone who has more knowledge than you is qualified to be your teacher. But only someone who understands the art as well as your goal is qualified to be your master. I have had many teachers in my life time but I have only had one master. A master can not only teach you the movements but also he can teach you how to conquer yourself. Our bad attitudes, impatience, anger etc. We all have very complicated problems that distract us from not only learning our martial arts style but also prevent us from becoming the best version of ourselves. I believe your true master will be able to teach the art while placing you on a path to your success in life. Which means you have to have a personal relationship.
If you are getting in to a classroom and it is your first time or you are a veteran you shouldn't be thinking about whether it is what you expected or not. The basics are NEVER exciting. The same stances or structures for hours on end is not something we look forward to. It is the transition from boy to man, man to warrior, warrior to master. If you just rush through them, you will always have the same weakness and eventuallly will have to start over anyway. So get it right the first time.