Should I charge extra for a payment plan?

Most operators don't. The plan closes a booking you might not have gotten, and the card fees on three payments versus one are noise. If a plan runs long on a big event, a small admin fee is defensible, but simplicity usually wins.

What's the smallest booking worth a payment plan?

Somewhere around 500 dollars for most operators. Below that, deposit plus balance is already two payments, and a third installment just adds admin.

What if the client wants to pay the rest in cash at the event?

Cash day-of works until the one time it doesn't. If you allow it, the confirmation states the exact amount and that setup begins after it's handed over. A card on file as backup makes the cash conversation relaxed.

Do payment plans increase cancellations?

The opposite, mostly. A client with three payments in has more committed, not less, and the deposit rules still apply. What increases cancellations is a distant event with nothing paid, which is exactly what a plan prevents.

Should I offer payment plans for party bookings?

For bookings over a few hundred dollars, yes. Two or three scheduled payments close larger events that a single upfront number would kill. The one rule that keeps plans safe: the final payment lands before the event date, never after.

Why plans win bookings

A 900 dollar school field day is an easy yes at 300 now, 300 next month, and 300 the week before. It's a committee meeting at 900 up front. Payment plans don't discount the party, they move the decision from "can we afford this today" to "is this worth it," which is the question you actually win.

Plans work hardest on:

Large events. Schools, towns, corporate. Bigger numbers, budget cycles, multiple approvers.
Far-out bookings. A party booked five months ahead splits naturally across the wait.
Peak dates. A premium Saturday is easier to commit to in installments.

For a standard backyard birthday booked three weeks out, a deposit plus one balance payment is already a payment plan. Don't complicate the small stuff.

The shape of a safe plan

Deposit at booking, same as always. The plan doesn't replace the deposit, it schedules the rest.
Two to four installments, on dates, not on promises. "The 1st of each month" beats "when I get paid."
Final payment at least 7 days before the event. This is the load-bearing rule. A plan that ends after the party is an unsecured loan to someone whose event is over.
Auto-charged to a card on file. A plan the client has to remember is a plan you have to chase. Card on file, charged on schedule, receipt sent.

What happens when an installment fails

Decide before it happens:

The card retries automatically over a few days. Most failures are expired cards and low balances that self-resolve.
If it's still unpaid, the client gets a message with a link to update the card.
If an installment is still open as the event approaches, the booking pauses until the plan is current. Written into the agreement, this is a status change, not a confrontation.

The line to remember

A payment plan is a schedule, not a favor. Put dates on it, put a card behind it, and end it before the party starts.