JVPC1969 gives a good answer. Here is my 5c. I am in the FMCG industry.
My philosophy on determining frequency is that we must prove that we are in control of our technology. We need to determine what calibration frequencies are - based on usage, environment, competence of users, and purpose of result generated etc.
New equipment: I agree that it can’t be assumed that equipment if fit-for purpose straight out of the box. We carry out a short verification on any element that has an effect on a result and have changed. This includes (but not limited to) new equipment, new chemical supplier, new analyst, new location etc.
For chromatography this verification would include –
Determine our needs. Based on this, determine
linearity range by injecting a minimum of 10 standards in triplicate. Repeatability (r) by analysing a minimum of 6 replicates and determining SD(r)Reproducibility (R) by analysing reference material and giving it the statistical treatment. (We are in the fortunate position of having access to large volumes of certified reference materials.)
If all the results meet our predefined requirements, verification is successful.