A validation rule on the Opportunity Product object to require custom date fields based on the product family will ensure that the data is captured properly. A validation rule can check if the product family matches the service plan and if so, require the start and end date fields to be filled out. This way, AW Computing can capture the term length for each service plan sold. References:
https://help.salesforce.com/s/articleView?id=sf.fields_about_validation_rules.htm&type=5