I take 900mg and dont feel numb. Im unsure of what it does. (But it must be working?)

I would not intentionally skip doses on lithium. I am pretty sure I experienced drug withdrawal from lithium when I would skip it all the time. (Back when I first started it)

The easiest way to remember meds is to take them in the same manner. I take lithium right before I sleep and have a kind of ritual around it. If its extended release you can take it at night and it will work during the day.