I have been taking between a 1,000 to 2000 units daily and just this year made it to 31.
My doctor looked at my labs on-line and sent message telling me to boost my intake to 2,000. I was crushed having finally made the goal of being low on the chart. I started immediately and had my appointment a few weeks later. During the appointment she asked how much I was taking I responded 2,000 since she told me to a few weeks earlier. Her response was that I should double that.
I decided that she had already told me to double it a few weeks earlier so I didn't boost my intake to 4,000 like she prescribed. I will see next year what my level is.
I'm doing better than I have in a long time but I also gave professional systems administration.