When should I shout? (shout option)

[Anik Roy]

Given that the underlying follows a random walk with drift path, when should I use the shout feature of a shout call option?

A shout option is the same thing as a european option but lets you "shout" once which will lock in the stock price at the time of the shout. The pay at expiration is max(S - X, Shout - X, Zero). Basically looking for the optimal time to shout thanks.

Thanks for your help guys!