The short answer: export every customer with the date of their last purchase or visit, work out how long your regulars normally wait between visits, and mark everyone who has been away two to three times that long as inactive. Then sort the list: former regulars first, bigger past orders second, one-time customers last. You need a spreadsheet, not special software.
Status: 7 November 2026. A practical guide, not legal advice. All example numbers are assumptions for illustration, not study results. Adjust them to your own data.
1. Why the list comes before the email
If you want to re-engage inactive customers, the message matters less than the list. Write to the wrong people and you annoy loyal customers who simply were on holiday, or you chase people who only ever bought once. A good list answers three questions: who has really stopped, who was worth keeping, and who should hear from you first.
2. Measure your own usual gap
A fixed cut-off such as "inactive after 90 days" may suit an online shop with monthly orders, but not a heating engineer whose customers call once a year. Measure instead:
- Pick 20 customers who bought at least three times over the past two or three years.
- For each one, write down the number of days between their purchases or visits.
- Sort all those gaps and take the one in the middle. That is your typical gap.
Now multiply by two or three. Anyone away longer than that is a candidate for your list. If your sample is small or the gaps vary a lot, take the longer multiple, so that you only contact people who have clearly stopped.
Example starting points, to be replaced by your own measurement:
| Type of business | Example typical gap | Example "inactive" mark |
|---|
| Café or lunch spot with regulars | 2 to 4 weeks | 2 to 3 months |
| Hair or beauty salon | 6 to 10 weeks | 5 to 6 months |
| Dental, physio or other practice | 6 to 12 months | 15 to 24 months |
| Trades with yearly service (heating, garden, cleaning) | 12 months | 2 to 3 years |
| Freelancer with repeat clients | 3 to 6 months | 9 to 12 months |
These figures are illustrative assumptions. They are not averages from a survey.
3. Where to get the list
You only need three columns to start: name, last purchase date, and a way to reach the person. Add number of purchases and total spent if you can. Where to find them:
- Invoices. Export your invoice list from your accounting tool, or list invoices by hand if you have few. Sort by customer, then keep only the newest row per customer. Count the rows you removed per customer: that is the number of purchases.
- Till or point-of-sale system. Many systems export sales by customer when you use a customer card or account. Customers who pay as walk-ins do not appear, and that is fine: you cannot contact them anyway.
- Booking or appointment system. Look for an export of past appointments with a date and client name. Filter for "last appointment" per client.
- Your own mailbox or paper files. For very small businesses, the sent-quotes folder or a box of customer cards is enough. Typing 50 names into a spreadsheet takes an evening and is worth it.
Use only the customer records you already hold from doing business together. Do not buy or borrow lists.
4. Mark who is inactive
In the spreadsheet, add a column "days since last purchase". If the last date is in column B, the formula is =TODAY()-B2, copied down. Then add a column "inactive?" that shows "yes" when the number of days is higher than your mark from section 2. Filter for "yes".
A fictional example with a small salon that uses a mark of 170 days:
| Name | Last visit | Visits | Days since | Inactive? |
|---|
| Client A | 12 Mar 2026 | 9 | 240 | yes |
| Client B | 02 Jun 2026 | 1 | 158 | no |
| Client C | 20 Apr 2026 | 4 | 201 | yes |
| Client D | 15 Jan 2026 | 1 | 296 | yes |
5. Clean the list before you use it
A raw "inactive" filter still contains people you should not contact. Remove customers with an open quote, open invoice or complaint, people who asked you to stop, and anyone who moved away or no longer fits your business. The checks in our guide on lapsed customers cover this in more detail, and the same guide points you to the official sources for marketing rules in your country. Read it before you send anything.
6. Whom to contact first
You rarely need to write to everyone at once. A sensible order, built on one idea: the customers most likely to come back and most worth keeping go first.
- Former regulars who stopped recently. Several purchases earlier, now just past your inactive mark. They know you, and they remember you.
- Customers with larger past orders. If a few people made up a big share of your sales, a personal call or a hand-written note may be worth more than a standard message.
- Former regulars who stopped long ago. Possible, but the reason for their absence may be one you cannot fix, like a move.
- One-time customers. Often the weakest group. Contact them last, or leave them out.
Split the list into waves of a size you can handle. If twenty people book on the same day, you must be able to answer all of them. Our guide on how many win-back emails to send shows what happens after the first wave.
7. Keep the list alive
- Add a column "contacted on" and one for the result: replied, booked, opted out, no reaction.
- Record opt-outs the same day and remove those people from every future list.
- Keep the spreadsheet private: store it in a protected place, share it with as few people as needed, and delete entries you no longer need.
- Repeat the export every quarter, or twice a year for slow businesses. A short monthly check is easier than a big yearly one.
- After a round, compare how many from each group came back. That tells you whether your inactive mark was too short or too long.
8. Common mistakes
- Copying a cut-off from an article. Your gap is the only number that counts.
- Treating one-time buyers like regulars. They were never "lost".
- Skipping the clean-up. Sending a "we miss you" note to someone with an open complaint is worse than sending nothing.
- Contacting the whole list on one day. You cannot handle the replies.
- Never checking the result. Without a record of who came back, you will repeat the same guess next time.
Frequently asked questions
How do I find inactive customers?
Export every customer with the date of their last purchase or visit, work out your usual gap, and mark anyone away two to three times that long as inactive.
How long without a purchase makes a customer inactive?
There is no universal number. It depends on how often your customers normally come back. Measure the gap in your own data and use a multiple of it, not a figure from an article.
Can I build a lapsed-customer list without a CRM?
Yes. A spreadsheet with name, last purchase date, number of purchases and total spent is enough. Invoices, till reports, booking history or even paper customer cards can fill it.
Whom should I contact first?
Start with former regulars who stopped most recently, then customers with larger past orders. Contact one-time customers last, or not at all.
Important: A practical aid, not legal advice. Check the marketing rules where you operate before you contact customers, yourself or with a professional.
Read on with a LeZo subscription
That was the beginning. The full guide with all sections is available when you sign in with a LeZo subscription.
Included in every LeZo subscription, from CHF 9 per month, cancel any time. For businesses, associations and self-employed people based in Switzerland. The subscription also unlocks all LeZo calculators and generators.
Already subscribed? Sign in and open «My account», or enter the licence key from your order e-mail.