Yes, you’re right, @Kimberly 1. Let me chime in and provide additional information about the recommendation above.
QuickBooks Desktop will keep your lists and preferences after the condensing process. Your general ledger, customers, and vendors' information will remain. All transactions you have for vendors and customers, including banks, will be removed. Documented balances will also wipe out.
If you want to keep some details from your old company file, especially the customer balances, I'd recommend taking notes or making a backup before performing the said utility. This way, you can access them anytime and ensure everything is intact.
I've got you a reference to learn more about condense limitations: Use the Condense Data utility.
If you have follow-up questions or other concerns about managing your company files, feel welcome to get back on this thread. I’ve got you covered. Have a good one and keep safe always!