Verifying IBANs before sending payments saves a lot of headaches down the line. A single incorrect digit can mean your money disappears into the banking system for days while they try to figure out what went wrong, and reversing those transactions is a nightmare of paperwork and fees. You can use this IBAN checker:
https://nimlab.eu/iban-checker/ . It validates the format and structure of the IBAN to make sure it's actually legitimate before you hit send on the transfer.