Separate first-year promotions from renewals
Registrars may discount an initial registration while charging the standard renewal rate later. Compare the ongoing price, not only the checkout total today.
Premium renewal rules can differ
Some registry-designated premium domains can carry elevated renewal pricing. That is different from an aftermarket premium domain whose higher cost is mainly the acquisition price.
Budget for a permanent asset
A primary business domain is meant to renew indefinitely. Even modest annual differences compound over the life of a company, so the extension's normal ownership cost belongs in the naming decision.