In our culture, we love to buy into the fantasy of overnight transformation, and seem to trust the exaggerated promises more when they are explicitly quantified: "Lose 30 pounds in 30 days!" "Double your money in ONE DAY!" "Read these 10 steps to happiness!"
Google "in 10 easy lessons" and you will be inundated with over 30 million hits promising to turn you into an instantaneous expert in a bewildering array of fields: blues piano, Perl computer language, psychic prediction, calligraphy, the Bible, dog training, speed reading....
Knowing that they have been surrounded by this type of advertising for years, I am not surprised that many prospective students ask me when they're inquiring about voice (or Alexander) lessons how many lessons they will need. Also, I can certainly understand that people like to know how new commitments they take on are going to consume their finite resources of money and time and energy. But I am always stymied as to how to answer the how-many-lessons question, because I suspect that it is not answerable—and think it might be interesting to analyze why this is so.
Why I can't tell you how many lessons you'll need:
First, you are unique. In the history of the world, no other person has had your particular combination of strengths and challenges. In order to begin to formulate an answer to the how-many question, I'd need to have a lot of information about the structure of your vocal cords, your musicality, your intelligence, your cooperativeness, your drive, the legacy of your previous training, and many other aspects of your physical and mental/emotional make-up. Considering that, after more than four decades, I'm still discovering new things about myself in these areas, I am unlikely to be able to formulate a complete enough evaluation of your qualities to know how they affect the amount of training you will need.
Second, the amount of training you will need depends on your goals. Do you want to be able to simply carry a tune. . .or do you want to be able to carry a spear while performing as Brünnhilde at the Metropolitan Opera? Every lesson you take has the potential to bring you a little closer to your goals: two lessons will bring you about twice as close. . . .
The main reason I can't tell you how many lessons you'll need is that learning to sing is not a matter of learning a finite list of facts. (If it were, I'd be selling a pdf version of that list on my website!) Learning to sing, like learning any complex skill, involves a never-ending process of self-discovery. Gradually, you will learn how to better get out of your own way, to allow your body to produce the sounds you want. I wrote "never-ending" because you needn't ever stop getting better and better at singing. (And you may discover that you actually enjoy the learning process, which can be physically, intellectually, and emotionally very satisfying.) Like a runner who keeps training to shave an extra second off his race time, you can continue to take voice lessons your whole life, incrementally extending your range or your expressive power or your ease in singing. My own musical education began over 40 years ago, and I am not planning to stop taking voice lessons until I can no longer make my way to my teacher's studio.
OK, maybe a lifetime of lessons is a bit much to contemplate if you're just starting to think about learning to sing. Start with a single lesson, and see how you like it. If you decide to continue, I recommend committing to at least a couple of months of lessons to give yourself a fair chance of seeing some results. You can of course stop at any time. . .but I'll bet you won't want to!