Fine-tuning
Definition
Further training a model on your own examples so its default behaviour shifts toward them. Distinct from prompting, which changes behaviour per request without changing the model.
Fine-tuning is worth it far less often than it is proposed. A detailed system prompt with a dozen strong examples reaches most of the benefit at a fraction of the cost and stays editable. Genuine fine-tuning earns its keep at high volume, on a narrow and stable task, where the examples number in the thousands.
The decisive question is whether your source material is consistent. A model fine-tuned on inconsistent copy reliably produces inconsistent copy, and you have now paid to make the inconsistency permanent.
Definitions are free.So is the cost review.
A short call, then a written review inside 72 hours: what your marketing costs, what it produces, and what is worth fixing first.