TIME TO FIRST USE — Used, Not Bought

A reorder rate tells you in month four what went wrong in week one. Time to first use tells you in week two. It’s the earliest retention number you can change.

The definition

For each monthly cohort of first-time buyers, count the days from delivery (not the order) to the first time the customer used the product. Report two things: the median, and the share who had used it by day 7, 14 and 30. Measure from delivery because shipping speed isn’t the customer’s delay. Report the median because a few very late users drag an average around. And keep the “not yet” group visible; at day 30, they are the people most of this guide is for.

Where the signal comes from

Direct signals. An app or device activation, a refill or cartridge, a login to a portal, a QR code on the insert that opens a “just used it” page. Best, where the product allows it.
A one-question survey. About ten days after delivery: “Have you used it yet?” with answers of today, 1 to 3 days after it came, 4 to 7, 8 to 14, and not yet. It’s the method most brands can start this week.
Proxies. How-to tickets and review dates. Useful as checks, not as the measure.

A survey has a catch. The people who answer are more likely to be the ones who used it, so the raw answers flatter you. The tool below asks how much less likely you think non-responders are to have used it and corrects for that. It also has a second catch, covered in chapter 10: asking about use changes use a little.

Run your numbers

Estimate a cohort’s time to first use

Example numbers. Replace with yours. Enter the share of respondents (or tracked buyers) who had used it by each day after delivery. Each figure includes the ones before it.

First-time buyers delivered in the cohort

Used by day 1

Used by day 3

Used by day 7

Used by day 14

Used by day 30

Share of the cohort these figures cover

How much less likely the rest are to have used it

median days from delivery to first use, corrected

of the cohort not yet used at day 14

of the cohort not yet used at day 30

buyers still unused at day 30

The correction assumes the buyers you didn’t hear from used it at a lower rate than those you did, by the percentage you enter, on every day. If you track use directly for every buyer, set coverage to 100%. The median is read off a straight line between the days you enter.

With the defaults, the raw survey says 52% used it within a week. Corrected for who answered, the median is about 11 days, 46% of the cohort still hasn’t used it at day 14, and about 750 of 2,000 buyers are still unused at day 30.

What good looks like

I don’t know of a published benchmark for time to first use in DTC, and I wouldn’t trust one if there were: a supplement and a pair of hiking boots have different natural first moments. My rule is to compare the product with its own use cycle. Anything used daily should have half its buyers started within three days of delivery. Anything used weekly, within a week. And whatever the product, the share still unused at day 30 should fall cohort by cohort.

Measure from delivery, report the median, and keep the “not yet” group in view.

Do this

Add the one-question survey to a message ten days after delivery, starting with this month’s first-time buyers. After two cohorts, put their answers in the estimator and put the median on your weekly page.

This is one chapter of Used, Not Bought, which is free and readable in full on a single page with no form in front of it.