Retirement calculations involve difficult, complex decisions

Q I am getting close to retirement and I am confused as to how much income I should plan on taking from my investment portfolios. I fear that I will be running out of money too soon and have no idea as to which portfolio I should take income from. Could you please offer some suggestions as to how I might proceed?Attempting to calculate these seemingly unlimited variables is turning out to be one of the most frustrating and confusing ordeals of my career.