Know what data you actually have
Export your customer list from the old system and look at what fields it includes: names, contact info, purchase history, loyalty points, and marked preferences. Not everything will transfer cleanly, so know what you're starting with.
Loyalty balances need special handling
If customers have earned points or store credit, decide how those balances move over before you import anything. Some platforms support direct loyalty migration; others require manually crediting balances after the fact.
Deduplicate before importing
Years of walk-in customers, phone orders and online accounts often create multiple records for the same person. Clean duplicates in the export file rather than importing them and sorting it out later.
Check consent and communication preferences
If you text or email customers marketing messages, confirm you have appropriate consent recorded and that opt-outs carry over. Don't start messaging an imported list without checking this first.
Protect sensitive information
Customer data should be handled carefully during export and import — avoid emailing spreadsheets with full contact lists back and forth insecurely, and delete working files once the migration is confirmed complete.
Verify after import
Spot-check a handful of customer profiles after import: confirm contact info, loyalty balance, and purchase history look right. Catching an error here is far easier than after a customer calls confused about a missing reward.