Inflation is always looming around the corner and can be the death of a portfolio! One of the best ways I have seen investors fight this portfolio risk is by holding both domestic and international equities. The key for every investor is balancing their equity risk-tolerance versus what is needed to keep up with inflation.
If you are ever tempted to stuff all your money under a mattress, pull out the latest graph showing the growth of $1 in equities/bonds/inflation, since 1925. That should change your mind in a heartbeat.