The short answer
Book event security as soon as the venue, date, attendance range, and basic format are known. Complex events need enough lead time for a site walk, risk review, staffing, public-safety coordination, post orders, and officer briefing. Holidays, major sporting or cultural weekends, multiple entrances, alcohol service, large crowds, or specialized credentials can make qualified personnel harder to schedule.
What to know
There is no responsible universal deadline. A small private event may be arranged with less notice if officers are available, while a festival, conference, concert, or multi-day program can require weeks or months of planning. Late requests may limit staffing choices and reduce the time available to coordinate the venue, police, fire, medical, parking, vendors, and accessibility needs.
When requesting a quote, provide the date, hours including setup and breakdown, address, expected attendance, age range, alcohol information, layout, entrances, parking, event history, known concerns, and duties requested. Ask when staffing becomes final and what cancellation or schedule-change terms apply. Arrow states that it accepts short-term and special-event work, but current lead time and availability must be confirmed directly.