When I add new customers they can have the same names.

A customer record with this ID already exists

. Is there any way I can allow customers to register names even if it exists?

I ran into this REAL PAIN as well. hoping someone has good solution. NS is using the name as the entity id key for the customer record. you can turn on auto numbering for customer record but then you start seeing Cust 00123 everywhere in the UI. It is a real pain to try and deal with that solution. The only hack I found was applying something unique to the last name saving record to get the name in the entity id for UI sake and then resetting the last name. When I feed customers from external transaction I append part of transaction id for example. I have a three step try catch that tries different methods. it just sucks.

I think if you do retail, I'd put auto-numbering for customer record on. If you have external systems, make sure you update NS withy your external system ID, or whichever direction vice versa. Both customerID and externalID is kinda forced unique. That or you allow override and since we're in the suitescript channel customize a different numbering system to populate the numbering ids. Whilst it isn't easy to implement it'd work.