the multiple portfolio approach mentioned has additional benefits depending on estate size and number/type of goals. most couples will have multiple goals and the risk assessment is best re-applied to each individual goal.
while a taxable account may be used for the income maintenance goal with a moderate to low risk level, a separate long term bequest only goal funded by a ROTH IRA might be best served by a 100% equity allocation
the point being that different goals may have different risk tolerance characteristics, and each might be better served with a unique allocation consistent with its individual profile.