i think it depends to what style and how much you are learning from your teacher.
you will need at least two years to develop a good skill at your basics like strikings and blockings and movements and combinations. some think that just learning the techniques is good enough, but knowing how to pull a trigger not going to guearantee that you will hit your target. to become "good" at you basics, i mean you are hitting with more power accuracy speed and explosiveness than any other person's "natural ability". what i mean is, you have above average power and speed and sensitivity. you cannot get this in a year seeing your teacher only sometimes. solo practice is not enough too, because you have to have his wisdom and comments about how your doing. do you believe that "practice makes perfect?". well thats not true, "perfect" practice makes perfect. other than that you are just practicing what you are doing, and that is not always correct.
now that, is just training your ability to strike and move. you will need at least two more years to learn how to fight. yeah you can learn how to hit somebody and whip his ass, but i am talking about truly learning strategy, not just saying, if he does this you can do that". what i am talking about is learnning to put all those "theory" to use. my image of "western FMA" artist, is a guy who likes to soak up as much information that he can so he can list his long resume and brag "i know this, i know that..." but he can only make this stuff work on his student and only if his student will go along with him. to many certifications go out without making this step, and teachers use the excuse "we train for life and death combat only". that is because they are afraid to fight, and they are afraid to make there students fight. so you end up with people who know techniques, but they dont have any courage and fake confidence, and still cant fight. you get this by fighting with people you dont know, and people who like to fight to. easiest place to find them? tournaments. not the classroom, that is where you practice your moves on people. the tournament and the sparring session is your battleground. if you want more "realism" more contact, then there are people around who will give you all the "realism" you want. unless you really dont want realism.
this is where you can call yourself "expert/black belter" now, your question about to master" something? you will need about 10 to 15 years of teaching, after your fighting careers best years are over. because while you are fighitng you will learn and come up with new ways to fight. then of course you will have to practice it and become "good" at it. if you do that while you are teaching, you will change your style many times and your going to have to develop your skill in those new things to. it will take many matches to develop a good fighting system, and they have to come from you, not from your teacher. the only person who can call himself a "master" is one who has his own system. because other than that, he is nothing more than a faithful student who stays with his teacher forever. about 10 years or more after you develop your system is a good time to be a master of something. you will have enough time to develop and research your fighting style, and enough time to see 3-4 generations of students who use it, and if it works. to say you are a master you are saying "my style is good enough i will put any of my boys against any other style any day, and i know it works because i did it, and they did it, and put your money where your mouth is". a guy who had nothing but seminar, theory and teaching seminar experience cant say that.
of course if you are a bad ass, and you will put your money where your mouth is now, you can just call yourself "master" anytime you want, but you will need to proved it.