It's calcium 2-3 times a week.
Multivitamins 1 time per month.
Calcium WITH d3 every 4-6 weeks.
I personally focus MORE on gut loading with foods that are rich in vitamins and high in calcium i.e drak green leafy vegetables, and my own dry gut load made of bee pollen, spirulina, wheat germ and brewers yeast.
As far as D3 supplemention, 4-6 weeks is fine. If you take your cham outside in the warmer months a few times a week, you don't need to give them D3 at all, which is why i can't wait for spring!