People need to check their D levels. One of my daughter felt she only needed 5,000 three days a week. I told her to check. She was surprised she came in at the 40 and has upped to a daily dose.
Well, I had been doing similar as your daughter. I've been taking about 5,000 IU almost everyday and a few days this winter taking 10,000.
I got my levels tested yesterday at a dentist's office of all places. Apparently, they like to check a person's Vit D levels before they do any implants as it greatly aids in healing. Only charged $65 but that was after like $900 of x-rays and to make a mold of the teeth. Should get the results soon.