When to send reorder emails: timing by product size

Why does timing matter more than the offer?

Because a reminder that arrives on the right day feels like help, and one that arrives early feels like an ad. If a customer still has half a bottle left, a 15%-off code won’t change much. If they used the last drop this morning, a simple “Running low?” email with a one-click reorder link does the job.

Good timing also protects your margin. When the moment is right, you rarely need a discount to win the second order.

How do I work out when a product runs out?

Use a simple sum, then check it against real orders.

• Step 1: find how much one use takes. Weigh the product before and after a week of normal use, ask your formulator, or ask a few loyal customers.
• Step 2: multiply by uses per day (morning, evening or both).
• Step 3: divide the size by daily use. That’s your run-out day.
• Step 4: subtract 5–7 days, so the new product arrives before the old one is empty.
• Step 5: compare with your data. In Shopify or Klaviyo, look at the median days between first and second order for that product, and adjust.

Example timing table

These numbers are a worked example to show the method. Your own product, dose and customers will differ, so test and adjust.

What should the reorder email say?

Keep it short and make reordering one tap.

• Subject: plain and personal, like “Running low on your [product]?”
• Body: one line on timing, one line on the result they’re getting, and a big button that adds the same product to the cart.
• Second chance: if they don’t reorder, send one more email 5–7 days later. This is where a small gift or a subscribe & save offer can help.
• A routine nudge: suggest the next step in their routine, not a random best-seller.

What if customers buy several products at once?

Time the reminder to the product that runs out first, and mention the others. If someone bought a serum and a cleanser together, remind them when the serum is due and add “need a new cleanser too?” with a link. Don’t send two separate reminders in the same week.

How we’d approach this at Cliktron

• Measure: pull the median days to second order for each best-seller.
• Model: build a run-out table per product and size.
• Build: one Klaviyo reorder flow with product-based delays, stopped by any new order.
• Test: compare reminder days (for example day 50 vs day 55) and offer vs no offer.
• Review: check repeat rate by product every month.

Your next step

Common mistakes

• One fixed delay for every product.
• Leading with a discount when the timing alone would work.
• Forgetting to stop the reminder once the customer reorders.
• Ignoring bundle and multi-buy orders, which last longer.
• Never checking the timing against real reorder data.