An interesting rule of thumb is that one cannot make Vitamin D if their shadow is longer than their height. Good thing to remember.
Dr. Bruce Hollis (who did an interesting study saying that it took a minimum of 6,500IU of D3 given to nursing mothers daily (IIRC, living in Atlanta where they make Vitamin D year-round) for their milk to contain enough Vitamin D to raise their babies' Vitamin D to sufficient levels), said there is no sense to taking less than 10,000IU of D3 daily.
If you were a nudist living in an area where you could make Vitamin D year-round, you would make about 10,000IU per day.
If a nudist making 10,000IU daily, supplemented with 10,000IU daily, they would still be way below the daily 46,000IU amount proven to cause hypercalcemia.
The half-life of D3 is about 2 months (Vitamin D made by your body has a slightly longer half-life), which means it would take about 6 months for blood levels to stabilize.
It is my opinion that one's Vitamin D level is something we should all track for life. So I wouldn't say don't get your Vitamin D levels checked. Although it's important to understand that as it takes 6 months to blood levels to stabilize, checking Vitamin D twice a year is probably good enough.
I live just 13 or so degrees above the equator, took 10,000IU daily for about 6 months, and noticed no adverse reactions. Blood Calcium is normal. Didn't measure urine Calcium because I don't care about that; if my Vitamin D was above 125 nmol/L I would expect urine Calcium to be higher because that's how we get rid of excess Calcium.
Recently, I read that high-levels of Vitamin D can increase E2 (can't remember if it was Aromatase or a different pathway/enzyme), and decreased my D3 to 5,000IU daily. I'm regretting that now (as I didn't know it took 6 months for blood levels to stabilize), but will ride it out for 6 months to see what happens.
I don't know if you'll feel better, but there is increasing evidence that Vitamin D is one of the most important things you can supplement.
So things to take away:
- Check your Vitamin D levels for life!
- Don't be afraid of D3 10,000IU daily.
Hope that helps.