On the Vercel platform, Serverless Function execution (GB-Hrs) will increase Bandwidth (GB) usage as well. Caching your Serverless Function reduces the GB-hours (Execution) of your Serverless Function, but does not reduce the Bandwidth usage that comes with executing your Serverless Function.
To reduce Bandwidth (GB) usage, you can investigate which Serverless Function has the highest execution values from the Usage tab in the Vercel Dashboard and work on optimizing the code for that function. Refer to Lowering Resource Usage in Vercel Projects for additional information on how to lower Bandwidth (GB) and Serverless Functions usage for your Vercel projects.
For usage guidelines, please check out our Typical Monthly Usage Guidelines documentation.