Related Clues:

• Aristocrat is surround­ed by unknowns on a regular basis
• Every 52 weeks
• Every 365 days
• Every tenth of a decade
• Every twelve months
• A hundred times a century
• Approximately every 52 weeks
• Every 365 or 366 days
• 'How do you measure, measure ___?' ('Rent' lyric)
• "Christmas comes but once ___"
• Birthday's ending soon, as it happens
• Yankees sheltered nobleman from time to time perhaps
• Dictator's too wise to entertain toff on a regular basis
• Checkup frequency, often
• Every September, say