For the first few years of the income tax, there were seven tax brackets for individual taxpayers, with rates ranging from 1 to 7 percent. (debt.org)
The ages of your spouse and children — This is helpful in determining how many years of income replacement your family would need if you were to die. (quotacy.com)
If you want to be more cautious, the number of years of income in bonds can be increased. (canadiancapitalist.com)