Actually it could be accomplished on ones first lucid dream, whether that means complete beginner or 5 years of no lucids. And another thing; you could technically live forever in 30 seconds, as paradoxical as it sounds, all you would have to do is continuously speed up your consciousness. Let's say you have one of our seconds out of the thirty left. Let's say in the dreamers time, they have 1 year left. Now what if they sped up their consciousness by 10 times by inducing another heart attack. Now they have 10 years left. You could do this indefinitely, so 0.0001 seconds could last you 1000 years of lucidity. Once you have reached the limits of your brain power, and you woke up, only 30 seconds would have gone by, in which you could induce another lucid heart attack and live another thousand years of lucidity.