Check within the process vs. checks of product

I was wondering if we have checks within the process to ensure the product is good, do they need to be calibrated even if we check the final product with calibrated instruments?

Answer:

The company must demonstrate that the measuring equipment is fit for purpose, therefore the measuring equipment must be calibrated or verified, or both, at specified intervals, or prior to use. Rationale that the final measures of the product will ensure its conformity and the measuring within the process doesn't have to be 100% reliable practically means that the measurement within the process is redundant. For more information, see: Monitoring and Measurement Equipment Control https://advisera.com/9001academy/blog/2014/05/06/monitoring-measurement-equipment-control/ the article is written based on ISO 9001:2008 but the requirements are the same