In 1983, a book entitled The Templeton Touch, by William Proctor, disclosed that one of Templeton's 22 principles for stock market investing was that stock price fluctuations are proportional to the square root of the price.
This video explains how the "velocity" of decay grows geometrically the closer we get to expiration. This video suggests shorting premium in the range of 30-50 days to expiration range.
