You can move existing customers to a new price three ways: raise everyone on the same day, tell them first with a window at the old price, or keep them on the old price for a set time. The first is cheapest on paper and most likely to cost you the customers the rise depends on.

Who hears first

1. SubscribersThe law sets how you tell them. In California, an automatic renewal business must give “a clear and conspicuous notice of the fee change” 7 to 30 days before it takes effect, with how to cancel, for agreements made, amended or extended since July 1, 2025 Published. In New York, you can’t charge a raised price without affirmative consent, or a window of at least 14 days after the charge to cancel with a pro rata refund Published. Other states differ; have counsel set your window.
2. Recent and repeat buyersEveryone who bought the affected SKUs in the last 90 days, and anyone who has ordered more than once. Tell them a week or two ahead and let them buy at the old price until the date.
3. Everyone elseThe site changes on the date. New visitors see one price and no announcement.

The California window runs both ways: a notice 60 days ahead doesn’t count, so send a second inside the 7 to 30 days. The Standing Order covers the mechanics, from pre-renewal reminders to how billing platforms apply a new price.

No loyal customer should learn the new price from a receipt.

The stock-up window

A week or two at the old price turns the announcement into a favor. It also pulls orders forward, so expect a spike before the date and a dip after, and read the result over the whole cycle (chapter 14). Cap quantities if a year’s supply at the old price would hurt.

Grandfathering is a cost you can count

Keeping existing customers on the old price costs you the rise on every order they place in the meantime. It pays only if it keeps enough of them who would otherwise have left. The tool compares raising them now with raising them after a grandfather period, over the same horizon.

With the defaults, three months at the old price costs $24,000 of the rise, keeps 150 customers who would have left, and comes out $14,880 ahead over two years. It pays as long as the delayed rise loses fewer than 4.5% of them, against 6% if you raised now. Stretch the period to twelve months and it loses: the rise you give up grows faster than the customers you keep.

The tool can’t tell you the two loss rates. Guess before the first rise, then measure them with the comparison in chapter 14 and rerun it before the next.

Rules for grandfathering

• Always an end date, announced at the start. Without one, it becomes a second price list nobody chose.
• Treat the end like a rise. Same notice windows, same reason, same way to cancel.
• Grandfather by relationship: subscribers and customers with two or more orders.
• Never grandfather new customers into a deal existing ones can’t have. That’s the loyalty tax from the other side.

Do this

• Decide the plan for each group: subscribers (window, grandfather, end date), repeat buyers (notice, stock-up window), everyone else (date). Run the tool at three and six months. Send counsel the subscriber notice.