Early bird pricing is a reduced rate offered for a limited window before registration moves to full price, used to pull attendee commitments forward.
Early bird pricing buys certainty. A discount available only until a fixed date pulls registrations forward, which gives you a usable headcount earlier, earlier cash, and a read on demand while there is still time to act on it. The discount is the price you pay for that information.
Far enough out that it genuinely changes behavior, close enough that the saving still feels real. A deadline eight weeks before an event that most people decide on three weeks out does nothing except discount your most committed buyers. Look at when registrations actually landed last year and set the date inside that curve.
Extending the deadline. It works once and teaches everyone that your deadlines are soft, which means next year nobody moves early and the discount becomes a pure giveaway. If the numbers are short, add a new reason to buy rather than reopening the old one.
Multiple price steps create repeated urgency and more administration. A single cutoff is simpler and easier to communicate. Tiers are worth it when registration runs over several months and you need more than one moment of pressure.