With the proper techniques, you can seriously gain so much within a few easy lessons. But, make sure you're using the correct techniques.
And as for a voice teacher, do your research and if possible opinions from their students. They may be great singers, but when it comes to teaching, ther are many rip-offs out there (ie $100-an-hour lessons for a year or two longer than is actually needed ... really: some teachers are that un-educated on teaching proper singing technique).
SAVE THE PALO ALTO BOWL!
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"And in the end, the love you take is equal to the love you make"
-- The Beatles
"Be the change you want to see in the world"
-- Mahatma Gandhi
"Celebrate Earth Day, every day"
-- John Denver
"Don't let them mold your mind, they want to control mankind, seems like their only intention is to exploit the earth; and you trust in their deceit, your mind causes your defeat, and so you become an invention to distort this earth; propoganda and lies, is a plague in our lives, how much more victimized, before we realize (hey) ... they'll make it attractive, to get man destracted, corrupting your (soul), polluting your (soul), destroying (your soul, mind control) ... ooh grand master, let the people go, you put them in total confusion, to downs-troy their soul; for they practise what you preach, so they're always in your reach, hi-tech slavery in these days, its mind control"
-- Stephen Marley