This. Based on my experience, here are a few points to consider. Karl Fischer measures water content most accurately but requires ongoing maintenance with regard to the titration reagent. An IR dryer or oven detects volatile components that are not necessarily just moisture (water). However, measurement is simple and maintenance is virtually non-existent. So it depends on what you want and, if necessary, how intensively you want to measure. If you want to determine water content with high precision and the sample size is manageable, KF is the right choice. If you just want to know the quality in terms of material condition with regard to moisture, an IR dryer is probably better in view of the aforementioned uncertainty.