That's a hard question to answer! I've been really wondering the same thing my self! I guess the before you can answer the question "how much silver is enough" you have to clearly define you purpose for stacking. Is it a retirement investment? Do you plan to sell immediately when the silver price goes up fairly high? Do you want to leave some for your children or relatives? For me, my stack is like a retirement savings so I want to keep stacking for a long long time! Thanks for the thoughts!