Really it is best to test your vitamin D levels once or twice a year...it should be in the 50-70 range for good health. There are many factors that can affect your ability to absorb vitamin D from the sun...I can attest to some of these variations as I have been taking D and testing for about 5 years. My husband, who is an avid outdoorsman, had levels under 30 because of some of these factors. He is now in the mid 60's range and his health has improved quite a bit after supplementing with D...10,000IU + 1 Super K daily during the winter and in the summer the same dose every other day.

https://www.health.harvard.edu/healthbeat/9-things-that-can-undermine-your-vitamin-d-level

Really it is best to test your vitamin D levels once or twice a year...it should be in the 50-70 range for good health. There are many factors that can affect your ability to absorb vitamin D from the sun...I can attest to some of these variations as I have been taking D and testing for about 5 years. My husband, who is an avid outdoorsman, had levels under 30 because of some of these factors. He is now in the mid 60's range and his health has improved quite a bit after supplementing with D...10,000IU + 1 Super K during the winter and in the summer the same dose every other day.

https://www.health.harvard.edu/healthbeat/9-things-that-can-undermine-your-vitamin-d-level