If you’re over 18, you’ve lived through two years whose dates are palindromes: 1991 and 2002. That’s a rare privilege. Since 1001, the normal gap between palindromic years has been 110 years (e.g., 1661-1771). The 11-year gap 1991-2002 has been the only exception, and we’ll wait a millennium for the next such gap, 2992-3003. Until then we’re back to 110-year intervals, and most people will see only one palindrome in a lifetime.

See Two Milestones.