How to Ride Stock Market Volatillity

I want to hear from certified financial planners and other financial experts from Long Island and the NYC metro area…I want to hear from you an explanation of WHY people are so often advised to stay the course? Saying that they should stay the course assumes that the people getting the advice have made the right asset allocation among stocks, bonds and cash for their situation (young, risk tolerant and saving for retirement, vs. old, nervous and in retirement). If you don’t have the right allocation, then you SHOULD make changes correct or not? When, if all, should you respond to market volatility? Or top 3-5 reasons why everyone should stay the course.