If you are in the automotive industry I would look in the AIAG MSA manual for general requirements for R&R. This general guideline is based on a 10%, 20%, 30% scale.
A realistic guideline should be determined based on the measurement discrimination required for the use of a specific gage. These guidelines should be noted in the appropriate areas of your quality system documentation.
R&R is a good place to start but the MSA system needs to evolve to determine bias, linearity, and stability.
This is a very general overview and I hope other members of the forum will have further input.